IPV4 to IPV6: IPv4/IPv6

IPv6 Quick Guide

Tukiyooo 1 IPv4/IPv6, IPv6, Overview, Setup IPv6 01:11

<h1>
Overview</h1>
<a href="http://ipv4-ipv6.blogspot.com/" target="_blank">Internet Protocol</a> version 6, is a new addressing protocol designed to
 incorporate whole sort of requirement of future internet known to us as
 Internet version 2. This protocol as its predecessor IPv4, works on 
Network Layer (Layer-3). Along with its offering of enormous amount of 
logical address space, this protocol has ample of features which 
addresses today’s shortcoming of IPv4. 
<h2>
Why new IP version?</h2>
So far, IPv4 has proven itself as a robust routable addressing 
protocol and has served human being for decades on its 
best-effort-delivery mechanism. It was designed in early 80’s and did 
not get any major change afterward. At the time of its birth, Internet 
was limited only to a few Universities for their research and to 
Department of Defense. IPv4 is 32 bits long which offers around 
4,294,967,296 (232) addresses. This address space was 
considered more than enough that time. Given below are major points 
which played key role in birth of IPv6: 
<ul class="list">
<li>Internet has grown exponentially and the address space allowed by
 IPv4 is saturating. There is a requirement of protocol which can 
satisfy the need of future Internet addresses which are expected to grow
 in an unexpected manner.</li>
<li>Using features such as NAT, has made the Internet discontiguous 
i.e. one part which belongs to intranet, primarily uses private IP 
addresses; which has to go through number of mechanism to reach the 
other part, the Internet, which is on public IP addresses.</li>
<li>IPv4 on its own does not provide any security feature which is 
vulnerable as data on Internet, which is a public domain, is never safe.
 Data has to be encrypted with some other security application before 
being sent on Internet.</li>
<li>Data prioritization in IPv4 is not up to date. Though IPv4 has 
few bits reserved for Type of Service or Quality of Service, but they do
 not provide much functionality.</li>
<li>IPv4 enabled clients can be configured manually or they need some
 address configuration mechanism. There exists no technique which can 
configure a device to have globally unique IP address.</li>
</ul>
<h2>
Why not IPv5?</h2>
Till date, Internet Protocol has been recognized has IPv4 only. 
Version 0 to 3 were used while the protocol was itself under development
 and experimental process. So, we can assume lots of background 
activities remain active before putting a protocol into production. 
Similarly, protocol version 5 was used while experimenting with stream 
protocol for internet. It is known to us as Internet Stream Protocol 
which used Internet Protocol number 5 to encapsulate its datagram. 
Though it was never brought into public use, but it was already used. 
Here is a table of IP version and their use:

<img alt="IPv6 Version Table" src="http://www.tutorialspoint.com/ipv6/images/ip_version_table.jpg" />
 
<h2>
Brief History</h2>
After IPv4’s development in early 80s, the available IPv4 address 
pool begun to shrink rapidly as the demand of addresses exponentially 
increased with Internet. Taking pre-cognizance of situation that might 
arise IETF, in 1994, initiated the development of an addressing protocol
 to replace IPv4. The progress of IPv6 can be tracked by means of RFC 
published: 
<ul class="list">
<li>1998 – RFC 2460 – Basic Protocol</li>
<li>2003 – RFC 2553 – Basic Socket API</li>
<li>2003 – RFC 3315 – DHCPv6</li>
<li>2004 – RFC 3775 – Mobile IPv6</li>
<li>2004 – RFC 3697 – Flow Label Specification</li>
<li>2006 – RFC 4291 – Address architecture (revision)</li>
<li>2006 – RFC 4294 – Node requirement</li>
</ul>
June 06, 2012 some of Internet giants chose to put their Servers on 
IPv6. Presently they are using Dual Stack mechanism to implement IPv6 
parallel with IPv4. 
<h1>
Features</h1>
The successor of IPv4 is not designed to be backward compatible. 
Trying to keep the basic functionalities of IP addressing, IPv6 is 
redesigned entirely. It offers the following features: 
<ul class="list">
<li> Larger Address Space:

In contrast to IPv4, IPv6 uses 4 times more bits to address a device on 
the Internet. This much of extra bits can provide approximately 
3.4×1038 different combinations of addresses. This address can 
accumulate the aggressive requirement of address allotment for almost 
everything in this world. According to an estimate, 1564 addresses can 
be allocated to every square meter of this earth.
</li>
<li>Simplified Header:

IPv6’s header has been simplified by moving all unnecessary information 
and options (which are present in IPv4 header) to the end of the IPv6 
header. IPv6 header is only twice as bigger than IPv4 providing the 
fact the IPv6 address is four times longer.
</li>
<li>End-to-end Connectivity:

Every system now has unique IP address and can traverse through the 
internet without using NAT or other translating components. After IPv6 
is fully implemented, every host can directly reach other host on the 
Internet, with some limitations involved like Firewall, Organization’s 
policies, etc.</li>
<li>Auto-configuration:

IPv6 supports both stateful and stateless auto configuration mode of its
 host devices. This way absence of a DHCP server does not put halt on 
inter segment communication. </li>
<li>Faster Forwarding/Routing:

Simplified header puts all unnecessary information at the end of the 
header. All information in first part of the header are adequate for a 
Router to take routing decision thus making routing decision as quickly 
as looking at the mandatory header.</li>
<li>IPSec:

Initially it was decided for IPv6 to must have IPSec security, making it
 more secure than IPv4. This feature has now been made optional.</li>
<li>No Broadcast:

Though Ethernet/Token Ring are considered as broadcast network because 
they support Broadcasting, IPv6 does not have any Broadcast support 
anymore left with it. It uses multicast to communicate with multiple 
hosts. </li>
<li>Anycast Support:

This is another characteristic of IPv6. IPv6 has introduced Anycast 
mode of packet routing. In this mode, multiple interfaces over the 
Internet are assigned same Anycast IP address. Routers, while routing, 
sends the packet to the nearest destination.</li>
<li>Mobility:

IPv6 was designed keeping mobility feature in mind. This feature 
enables hosts (such as mobile phone) to roam around in different 
geographical area and remain connected with same IP address. IPv6 
mobility feature takes advantage of auto IP configuration and Extension 
headers.</li>
<li>Enhanced Priority support:

Where IPv4 used 6 bits DSCP (Differential Service Code Point) and 2 bits
 ECN (Explicit Congestion Notification) to provide Quality of Service 
but it could only be used if the end-to-end devices support it, that is,
 the source and destination device and underlying network must support 
it. 
 
 
In IPv6, Traffic class and Flow label are used to tell underlying routers how to efficiently process the packet and route it.</li>
<li>Smooth Transition:

Large IP address scheme in IPv6 enables to allocate devices with 
globally unique IP addresses. This assures that mechanism to save IP 
addresses such as NAT is not required. So devices can send/receive data
 between each other, for example VoIP and/or any streaming media can be 
used much efficiently.

Other fact is, the header is less loaded so routers can make forwarding decision and forward them as quickly as they arrive.</li>
<li>Extensibility:

One of the major advantage of IPv6 header is that it is extensible to 
add more information in the option part. IPv4 provides only 40-bytes 
for options whereas options in IPv6 can be as much as the size of IPv6 
packet itself.</li>
</ul>
<h1>
Addressing Modes</h1>
In computer networking, addressing mode refers to the mechanism how 
we address a host on the network. IPv6 offers several types of modes by
 which a single host can be addressed, more than one host can be 
addressed at once or the host at closest distance can be addressed. 
<h2>
Unicast</h2>
In unicast mode of addressing, an IPv6 interface (host) is uniquely 
identified in a network segment. The IPv6 packet contains both source 
and destination IP addresses. A host interface is equipped with an IP 
address which is unique in that network segment. A network switch or 
router when receives a unicast IP packet, destined to single host, sends
 out to one of its outgoing interface which connects to that particular 
host. 
<figure>
<img caption="Unicast Messaging" src="http://www.tutorialspoint.com/ipv6/images/unicast.jpg" />
<figcaption align="center">[Image: Unicast Messaging]</figcaption>
</figure><h2>
Multicast</h2>
The IPv6 multicast mode is same as that of IPv4. The packet destined
 to multiple hosts is sent on a special multicast address. All hosts 
interested in that multicast information, need to join that multicast 
group first. All interfaces which have joined the group receive the 
multicast packet and process it, while other hosts not interested in 
multicast packets ignore the multicast information.

<figure>
<img caption="Multicast Messaging" src="http://www.tutorialspoint.com/ipv6/images/multicast.jpg" />
<figcaption align="center">[Image: Multicast Messaging]</figcaption>
</figure><h2>
Anycast</h2>
IPv6 has introduced a new type of addressing, which is called Anycast
 addressing. In this addressing mode, multiple interfaces (hosts) are 
assigned same Anycast IP address. When a host wishes to communicate 
with a host equipped with an Anycast IP address, sends a Unicast 
message. With the help of complex routing mechanism, that Unicast 
message is delivered to the host closest to the Sender, in terms of 
Routing cost. 
<figure>
<img caption="Anycast Messaging" src="http://www.tutorialspoint.com/ipv6/images/anycast.jpg" />
<figcaption align="center">[Image: Anycast Messaging]</figcaption>
</figure>Let’s take an example of TutorialPoints.com Web Servers, located in 
all continents. Assume that all Web Servers are assigned single IPv6 
Anycast IP Address. Now when a user from Europe wants to reach 
TutorialsPoint.com the DNS points to the server which is physically 
located in Europe itself. If a user from India tries to reach 
Tutorialspoint.com, the DNS will then point to Web Server physically 
located in Asia only. Nearest or Closest terms are used in terms of 
Routing Cost. 
In the above picture, When a client computer tries to reach a Server,
 the request is forwarded to the Server with lowest Routing Cost. 
<h1>
Address Types</h1>
<h2>
Hexadecimal Number System</h2>
Before introducing IPv6 Address format, we shall look into 
Hexadecimal Number System. Hexadecimal is positional number system 
which uses radix (base) of 16. To represent the values in readable 
format, this system uses 0-9 symbols to represent values from zero to 
nine and A-F symbol to represent values from ten to fifteen. Every 
digit in Hexadecimal can represent values from 0 to 15. 
<figure>
<img caption="Hexadecimal Conversion Table" src="http://www.tutorialspoint.com/ipv6/images/Hexadecimal_conversion_table.jpg" />
<figcaption align="center">[Image: Conversion Table]</figcaption>
</figure><h2>
Address Structure</h2>
An IPv6 address is made of 128 bits divided into eight 16-bits 
blocks. Each block is then converted into 4-digit Hexadecimal numbers 
separated by colon symbol.

For example, the below is 128 bit IPv6 address represented in binary format and divided into eight 16-bits blocks: 
<blockquote>
0010000000000001 0000000000000000 0011001000110100 1101111111100001 
0000000001100011 0000000000000000 0000000000000000 1111111011111011</blockquote>
Each block is then converted into Hexadecimal and separated by ‘:’ symbol: 
<blockquote>
2001:0000:3238:DFE1:0063:0000:0000:FEFB</blockquote>
Even after converting into Hexadecimal format, IPv6 address remains 
long. IPv6 provides some rules to shorten the address. These rules 
are: 
Rule:1 Discard leading Zero(es): 
In Block 5, 0063, the leading two 0s can be omitted, such as (5th block): 
<blockquote>
2001:0000:3238:DFE1:63:0000:0000:FEFB</blockquote>
Rule:2 If two of more blocks contains consecutive zeroes, omit
 them all and replace with double colon sign ::, such as (6th and 7th 
block): 
<blockquote>
2001:0000:3238:DFE1:63::FEFB</blockquote>
Consecutive blocks of zeroes can be replaced only once by :: so if 
there are still blocks of zeroes in the address they can be shrink down 
to single zero, such as (2nd block): 
<blockquote>
2001:0:3238:DFE1:63::FEFB</blockquote>
<h2>
Interface ID</h2>
IPv6 has three different type of Unicast Address scheme. The second 
half of the address (last 64 bits) is always used for Interface ID. MAC
 address of a system is composed of 48-bits and represented in 
Hexadecimal. MAC address is considered to be uniquely assigned 
worldwide. Interface ID takes advantage of this uniqueness of MAC 
addresses. A host can auto-configure its Interface ID by using IEEE’s 
Extended Unique Identifier (EUI-64) format. First, a Host divides its 
own MAC address into two 24-bits halves. Then 16-bit Hex value 0xFFFE 
is sandwiched into those two halves of MAC address, resulting in 64-bit 
Interface ID. 
<figure>
<img caption="EUI-64: Interface ID" src="http://www.tutorialspoint.com/ipv6/images/interface_id.jpg" />
<figcaption align="center">[Image: EUI-64 Interface ID]</figcaption>
</figure><h2>
Global Unicast Address</h2>
This address type is equivalent to IPv4’s public address. Global 
Unicast addresses in IPv6 are globally identifiable and uniquely 
addressable. 
<figure>
<img caption="Global Unicast Address" src="http://www.tutorialspoint.com/ipv6/images/global_unicast_address.jpg" />
<figcaption align="center">[Image: Global Unicast Address]</figcaption>
</figure>Global Routing Prefix: The most significant 48-bits are designated as
 Global Routing Prefix which is assigned to specific Autonomous System. 
 Three most significant bits of Global Routing Prefix is always set to 
001. 
<h2>
Link-Local Address</h2>
Auto-configured IPv6 address is known as Link-Local address. This 
address always starts with FE80. First 16 bits of Link-Local address is
 always set to 1111 1110 1000 0000 (FE80). Next 48-bits are set to 0, 
thus: 
<figure style="margin: 0px; padding: 0px;">
<img caption="Link-Local Address" src="http://www.tutorialspoint.com/ipv6/images/link_local_address.jpg" />
<figcaption align="center">[Image: Link-Local Address]</figcaption>
</figure>Link-Local addresses are used for communication among IPv6 hosts on a
 link (broadcast segment) only. These addresses are not routable so a 
Router never forwards these addresses outside the link. 
<h2>
Unique-Local Address</h2>
This type of IPv6 address which is though globally unique, but it 
should be used in local communication. This address has second half of 
Interface ID and first half is divided among Prefix, Local Bit, Global 
ID and Subnet ID. 
<figure style="margin: 0px; padding: 0px;">
<img caption="Unique-Local Address" src="http://www.tutorialspoint.com/ipv6/images/unique_local_address.jpg" />
<figcaption align="center">[Image: Unique-Local Address]</figcaption>
</figure>
Prefix is always set to 1111 110. 
L bit, which is set to 1 if the address is locally assigned. So far the meaning of L bit to 0 is not defined.
Therefore, Unique Local IPv6 address always starts with ‘FD’.
 
<h3>
Scope of IPv6 Unicast Addresses:</h3>
<figure>
<img caption="IPv6 Unicast Address Scope" src="http://www.tutorialspoint.com/ipv6/images/address_scope.jpg" />
<figcaption align="center">[Image: IPv6 Unicast Address Scope]</figcaption>
</figure>The scope of Link-local address is limited to the segment. Unique 
Local Address are though locally global but are not routed over the 
Internet, limiting their scope to an organization’s boundary. Global 
Unicast addresses are globally unique and recognizable. They shall make
 the essence of Internet v2 addressing. 
<h1>
Special Addresses</h1>
Version 6 has slightly complex structure of IP address than that of 
IPv4. IPv6 has reserved few addresses and address notations for special
 purposes. See the table below: 
<h2>
Special Addresses:</h2>
<img caption="Special Address" src="http://www.tutorialspoint.com/ipv6/images/special_address_table.jpg" />
 
<ul class="list">
<li>As shown in the table above 0:0:0:0:0:0:0:0/128 address does not 
specify to anything and is said to be an unspecified address. After 
simplifying, all 0s are compacted to ::/128.</li>
<li>In IPv4, address 0.0.0.0 with netmask 0.0.0.0 represents default 
route. The same concept is also applie to IPv6, address 0:0:0:0:0:0:0:0
 with netmask all 0s represents default route. After applying IPv6 
simplying rule this address is compressed to ::/0.</li>
<li>Loopback addresses in IPv4 are represented by 127.0.0.1 to 
127.255.255.255 series. But in IPv6, only 0:0:0:0:0:0:0:1/128 address 
represents Loopback address. After simplying loopback address, it can 
be represented as ::1/128.</li>
</ul>
<h2>
Reserved Multicast Address for Routing Protocols:</h2>
<img caption="Multicast Routing Addresses" src="http://www.tutorialspoint.com/ipv6/images/reserved_multicast_routing_address.jpg" />
 
<ul class="list">
<li>The above table shows reserved multicast addresses used by interior routing protocol. 
</li>
<li>All addresses are reserved in similar IPv4 fashion</li>
</ul>
<h2>
Reserved Multicast Address for Routers/Node:</h2>
<img caption="Multicast addresses for routers and nodes" src="http://www.tutorialspoint.com/ipv6/images/reserved_multicast_routers_nodes_address.jpg" />
 
<ul class="list">
<li>These addresses helps routers and hosts to speak to available 
routers and hosts on a segment without being configured with an IPv6 
address. Hosts use EUI-64 based auto-configuration to self-configure an
 IPv6 address and then speaks to available hosts/routers on the segment 
by means of these addresses.</li>
</ul>
<h1>
Headers</h1>
The wonder of IPv6 lies in its header. IPv6 address is 4 times 
larger than IPv4 but the IPv6 header is only 2 times larger than that of
 IPv4. IPv6 headers have one Fixed Header and zero or more Optional 
(Extension) Headers. All necessary information which is essential for a
 router is kept in Fixed Header. Extension Header contains optional 
information which helps routers to understand how to handle a 
packet/flow. 
<h2>
Fixed Header</h2>
<figure style="margin: 0px; padding: 0px;">
<img caption="IPv6 Fixed Header" src="http://www.tutorialspoint.com/ipv6/images/IPv6_header.jpg" />
<figcaption align="center">[Image: IPv6 Fixed Header]</figcaption>
</figure>IPv6 fixed header is 40 bytes long and contains the following information. 
<table class="src">
<tbody>
<tr><th style="width: 5%;">S.N.</th><th>Field & Description</th></tr>
<tr><td>1</td><td>Version (4-bits): This represents the version of Internet Protocol, i.e. 0110.</td></tr>
<tr><td>2</td><td>Traffic Class (8-bits): These 8 bits are 
divided into two parts. Most significant 6 bits are used for Type of 
Service, which tells the Router what services should be provided to this
 packet. Least significant 2 bits are used for Explicit Congestion 
Notification (ECN).</td></tr>
<tr><td>3</td><td>Flow Label (20-bits): This label is used to 
maintain the sequential flow of the packets belonging to a 
communication. The source labels the sequence which helps the router to
 identify that this packet belongs to a specific flow of information. 
This field helps to avoid re-ordering of data packets. It is designed 
for streaming/real-time media.</td></tr>
<tr><td>4</td><td>Payload Length (16-bits): This field is used
 to tell the routers how much information this packet contains in its 
payload. Payload is composed of Extension Headers and Upper Layer data.
 With 16 bits, up to 65535 bytes can be indicated but if Extension 
Headers contain Hop-by-Hop Extension Header than payload may exceed 
65535 bytes and this field is set to 0.</td></tr>
<tr><td>5</td><td>Next Header (8-bits): This field is used to 
indicate either the type of Extension Header, or if Extension Header is 
not present then it indicates the Upper Layer PDU. The values for the 
type of Upper Layer PDU is same as IPv4’s.</td></tr>
<tr><td>6</td><td>Hop Limit (8-bits): This field is used to 
stop packet to loop in the network infinitely. This is same as TTL in 
IPv4. The value of Hop Limit field is decremented by 1 as it passes a 
link (router/hop). When the field reaches 0 the packet is discarded.</td></tr>
<tr><td>7</td><td>Source Address (128-bits): This field indicates the address of originator of the packet.</td></tr>
<tr><td>8</td><td>Destination Address (128-bits): This field provides the address of intended recipient of the packet.</td></tr>
</tbody></table>
<h2>
Extension Headers</h2>
In IPv6, the Fixed Header contains only information which is 
necessary and avoiding information which is either not required or is 
rarely used. All such information, is put between the Fixed Header and 
Upper layer header in the form of Extension Headers. Each Extension 
Header is identified by a distinct value. 
When Extension Headers are used, IPv6 Fixed Header’s Next Header 
field points to the first Extension Header. If there is one more 
Extension Header, then first Extension Header’s ‘Next-Header’ field 
point to the second one, and so on. The last Extension Header’s 
‘Next-Header’ field point to Upper Layer Header. Thus all headers from 
point to the next one in a linked list manner. 
If the Next Header field contains value 59, it indicates that there’s no header after this header, not even Upper Layer Header. 
The following Extension Headers must be supported as per RFC 2460:

<img caption="Extension Headers" src="http://www.tutorialspoint.com/ipv6/images/extension_headers.jpg" />
 
The sequence of Extension Headers should be:

<img caption="Extension Headers Sequence" src="http://www.tutorialspoint.com/ipv6/images/extension_headers_sequence.jpg" />
 
These headers: 
<ul class="list">
<li>1. Should be processed by First and subsequent destinations.</li>
<li>2. Should be processed by Final Destination. </li>
</ul>
Extension Headers are arranged one after another in a Linked list manner, as depicted in the diagram below: 
<figure style="margin: 0px; padding: 0px;">
<img caption="Extension Headers Connection" src="http://www.tutorialspoint.com/ipv6/images/extension_header_sequence.jpg" />
<figcaption align="center">[Image: Extension Headers Connected Format]</figcaption>
</figure><h1>
Communication</h1>
In IPv4, a host which wants to communicate with some other host on 
the network, needs first to have an IP address acquired either by means 
of DHCP or by manual configuration. As soon as a host is equipped with 
some valid IP address, it is now able to speak to any host on the 
subnet. To communicate on layer-3, a host also must know the IP address
 of the other host. Communication on a link, is established by means of
 hardware embedded MAC Addresses. To know the MAC address of host whose
 IP address is known, a host sends ARP broadcast and in revert the 
intended host sends back its MAC address. 
In IPv6, there’s no broadcast mechanism. It is not a must for an 
IPv6 enabled host to obtain IP address from DHCP or manually configured,
 but it can auto-configure its own IP. Then, how would a host 
communicates with others on IPv6 enabled network? 
ARP has been replaced by ICMPv6 Neighbor Discovery Protocol. 
<h2>
Neighbor Discovery Protocol</h2>
A host in IPv6 network is capable of auto-configuring itself with a 
unique link-local address. As soon as it is equipped with an IPv6 
address, it joins a number of multicast groups. All communications 
related to that segment happens on those multicast addresses only. A 
host goes through a series of states in IPv6: 
<ul class="list">
<li>Neighbor Solicitation: After configuring all IPv6’s either
 manually, or by DHCP Server or by auto-configuration, the host sends a 
Neighbor Solicitation message out to FF02::1/16 multicast address for 
all its IPv6 addresses in order to know that no one else occupies same 
addresses.</li>
<li>DAD (Duplicate Address Detection): When the host does not 
listen from anything from the segment regarding its Neighbor 
Solicitation message, it assumes that no duplicate address exists on the
 segment.</li>
<li>Neighbor Advertisement: After assigning the addresses to 
its interfaces and making them up and running, the host once again sends
 out a Neighbor Advertisement message telling all other hosts on the 
segment, that it has assigned those IPv6 addresses to its interfaces.</li>
</ul>
Once a host is done with the configuration of its IPv6 addresses, it does the following things: 
<ul class="list">
<li>Router Solicitation: A host sends a Router Solicitation 
multicast packet (FF02::2/16) out on its segment to know the presence of
 any router on this segment. This helps the host to configure the 
router as its default gateway. If its default gateway router goes down,
 the host can shift to a new router and makes it the default gateway.</li>
<li>Router Advertisement: When a router receives a Router Solicitation message, it responses back to the host advertising its presence on that link.</li>
<li>Redirect: This may be the situation where a Router 
receives a Router Solicitation request but it knows that it is not the 
best gateway for the host. In this situation, the router sends back a 
Redirect message telling the host that there is a better ‘next-hop’ 
router available. Next-hop is where the host will send its data 
destined to a host which does not belong to the same segment.</li>
</ul>
<h1>
Subnetting</h1>
In IPv4, addresses were created in classes. Classful IPv4 addresses 
clearly defines the bits used for network prefixes and the bits used for
 hosts on that network. To subnet in IPv4 we play with the default 
classful netmask which allows us to borrow hosts bit to be used as 
subnet bits. This results in multiple subnets but less hosts per 
subnet. That is, when we borrow host bit to create a subnet that costs 
us in lesser bit to be used for host addresses. 
IPv6 addresses uses 128 bits to represent an address which includes 
bits to be used for subnetting. Second half of the address (least 
significant 64 bits) is always used for Hosts only. Therefore, there is
 no compromise if we subnet the network. 
<figure>
<img caption="IPv6 Subnetting" src="http://www.tutorialspoint.com/ipv6/images/subnetting.jpg" />
<figcaption align="center">[Image: IPv6 Subnetting]</figcaption>
</figure>16 Bits of subnet is equivalent to IPv4’s Class B Network. Using 
these subnet bits an organization can have more 65 thousands of subnets 
which is by far, more than enough. 
Thus routing prefix is /64 and host portion is 64 bits. We though, 
can further subnet the network beyond 16 bits of Subnet ID, borrowing 
hosts bit but it is recommended that 64 bits should always be used for 
hosts addresses because auto-configuration requires 64 bits. 
IPv6 subnetting works on the same concept as Variable Length Subnet Masking in IPv4. 
/48 prefix can be allocated to an organization providing it the 
benefit of having up to /64 subnet prefixes, which is 65535 
sub-networks, each having 264 hosts. A /64 prefix can be assigned to a 
point-to-point connection where there are only two hosts (or IPv6 
enabled devices) on a link. 
<h1>
IPv4 to IPv6</h1>
One problem in transition from IPv4 to IPv6 completely is that IPv6 
is not backward compatible. This results in a situation where either a 
site is on IPv6 or it is not. Unlike an implementation of new 
technology where the newer one is backward compatible so the older 
system can still work with the newer without any additional changes. 
To overcome this short-coming, there exist few technologies which can be used in slow and smooth transition from IPv4 to IPv6: 
<h2>
Dual Stack Routers</h2>
A router can be installed with both IPv4 and IPv6 addresses 
configured on its interfaces pointing to the network of relevant IP 
scheme. 
<figure>
<img caption="Dual Stack Router" src="http://www.tutorialspoint.com/ipv6/images/dual_stack_router.jpg" />
<figcaption align="center">[Image: Dual Stack Router]</figcaption>
</figure>In above diagram, a Server which is having IPv4 as well as IPv6 
address configured for it now can speak with all hosts on IPv4 network 
and IPv6 network with help of Dual Stack Router. Dual Stack Router, can
 communicate with both networks and provides a medium for hosts to 
access Server without changing their respective IP version. 
<h2>
Tunneling</h2>
In a scenario where different IP versions exist on intermediate path 
or transit network, tunneling provides a better solution where user’s 
data can pass through a non-supported IP version. 
<figure>
<img caption="Tunneling" src="http://www.tutorialspoint.com/ipv6/images/tunneling.jpg" />
<figcaption align="center">[Image: Tunneling]</figcaption>
</figure>The above diagram depicts how two remote IPv4 networks can 
communicate via Tunnel, where the transit network was on IPv6. Vice 
versa is also possible where transit network is on IPv6 and remote sites
 which intends to communicate, are on IPv4. 
<h2>
NAT Protocol Translation</h2>
This is another important method of transition to IPv6 by means of a 
NAT-PT (Network Address Translation – Protocol Translation) enabled 
device. With help of NAT-PT device, actual conversion happens between 
IPv4 and IPv6 packets and vice versa. See the diagram below: 
<figure>
<img caption="NAT-PT" src="http://www.tutorialspoint.com/ipv6/images/nat.jpg" />
<figcaption align="center">[Image: NAT - Protocol Translation]</figcaption>
</figure>A host with IPv4 address sends a request to IPv6 enabled Server on 
Internet which does not understand IPv4 address. In this scenario, 
NAT-PT device can help them communicate. When IPv4 host sends a request
 packet to IPv6 Server, NAT-PT device/router, strips down the IPv4 
packet, removes IPv4 header and adds IPv6 header and passes it through 
the Internet. When a response from IPv6 Server comes for IPv4 host, the
 router does vice versa. 
<h1>
Mobility</h1>
When a host is connected to one link or network, it acquires an IP 
address and all communication happens using that IP address on that 
link. As soon as, the same host changes its physical location, that is,
 moves into some different area / subnet / network / link, its IP 
address changes accordingly and all communication happening on the host 
using old IP address, goes down. 
IPv6 mobility provides a mechanism which equips a host with an 
ability to roam around among different links without losing any 
communication/connection and its IP address. 
Multiple entities are involved in this technology: 
<ul class="list">
<li>Mobile Node: The device which needs IPv6 mobility. </li>
<li>Home Link: This link is configured with the home subnet prefix and this is where the Mobile IPv6 device gets its Home Address.</li>
<li>Home Address: This is the address which Mobile Node 
acquires from Home Link. This is permanent address of Mobile Node. If 
the Mobile Node remains in the same Home Link, the communication among 
various entities happens as usual.</li>
<li>Home Agent: This is a router which acts as registrar for 
Mobile Nodes. Home Agent is connected to Home Link and maintains 
information about all Mobile Nodes, their Home Addresses and their 
present IP addresses.</li>
<li>Foreign Link: Any other Link which is not Mobile Node’s Home Link.</li>
<li>Care-of Address: When a Mobile Node attaches to a Foreign 
Link, it acquires a new IP address of that Foreign Link’s subnet. Home 
Agent maintains the information of both Home Address and Care-of 
Address. Multiple Care-of addresses can be assigned to Mobile Node, but
 at any instance only one Care-of Address has binding with Home Address.</li>
<li>Correspondent Node: Any IPv6 enable device which intends to have communication with Mobile Node.</li>
</ul>
<h2>
Mobility Operation</h2>
When Mobile Node stays in its Home Link, all communications happen on its Home Address. As shown below: 
<figure>
<img caption="Mobile Node in Home Link" src="http://www.tutorialspoint.com/ipv6/images/MN_in_HL.jpg" />
<figcaption align="center">[Image: Mobile Node connected to Home Link]</figcaption>
</figure>When Mobile Node leaves its Home Link and is connected to some 
Foreign Link, the Mobility feature of IPv6 comes into play. After 
connecting to Foreign Link, Mobile Node acquires an IPv6 address from 
Foreign Link. This address is called Care-of Address. Mobile Node 
sends binding request to its Home Agent with the new Care-of Address. 
Home Agent binds Mobile Node’s Home Address with Care-of Address, 
establishing a Tunnel between both. 
Whenever a Correspondent Node tries to establish connection with 
Mobile Node (on its Home Address), the Home Agent intercepts the packet 
and forwards to Mobile Node’s Care-of Address over the Tunnel which was 
already established. 
<figure>
<img caption="Mobile Node in Foreign Link" src="http://www.tutorialspoint.com/ipv6/images/MN_in_FL.jpg" /> 
<figcaption align="center">[Image: Mobile Node connected to Foreign Link]</figcaption>
</figure><h2>
Route Optimization</h2>
When a Correspondent Node initiate communication by sending packets 
to Mobile Node on Home Address, these packets are tunneled to Mobile 
Node by Home Agent. In Route Optimization mode, when the Mobile Node 
receives packet from Correspondent Node, it does not forward replies to 
Home Agent. Rather it sends its packet directly to Correspondent Node 
using Home Address as Source Address. This mode is optional and not 
used by default. 
<h1>
Routing</h1>
Routing concepts remain same in case of IPv6 but almost all routing 
protocol have been redefined accordingly. We have seen in Communication
 in IPv6 segment, how a host speaks to its gateway. Routing is a 
process to forward routable data choosing best route among several 
available routes or path to the destination. A router is a device which
 forwards data which is not explicitly destined to it. 
There exists two forms of routing protocols 
<ul class="list">
<li>Distance Vector Routing Protocol: A 
router running distance vector protocol advertises its connected routes 
and learns new routes from its neighbors. The routing cost to reach a 
destination is calculated by means of hops between the source and 
destination. A Router generally relies on its neighbor for best path 
selection, also known as “routing-by-rumors”. RIP and BGP are Distance 
Vector Protocols.</li>
<li>Link-State Routing Protocol: This protocol acknowledges 
the state of a Link and advertises to its neighbors. Information about 
new links is learnt from peer routers. After all the routing 
information has been converged, Link-State Routing Protocol uses its own
 algorithm to calculate best path to all available links. OSPF and 
IS-IS are link state routing protocols and both uses Djikstra’s Shortest
 Path First algorithm.</li>
</ul>
Routing protocols can be divided in two categories: 
<ul class="list">
<li>Interior Routing Protocol: Protocols in 
this categories are used within an Autonomous System or organization to 
distribute routes among all routers inside its boundary. Examples: RIP,
 OSPF.</li>
<li>Exterior Routing Protocol: Whereas an Exterior Routing 
Protocol distributes routing information between two different 
Autonomous Systems or organization. Examples: BGP.</li>
</ul>
<h2>
Routing protocols</h2>
<ul class="list">
<li>RIPng

RIPng stands for Routing Information Protocol Next Generation. This 
is an Interior Routing Protocol and is a Distance Vector Protocol. 
RIPng has been upgraded to support IPv6.

</li>
<li>OSPFv3</li>
Open Shortest Path First version 3 is an Interior Routing Protocol 
which is modified to support IPv6. This is a Link-State Protocol and 
uses Djikrasta’s Shortest Path First algorithm to calculate best path to
 all destinations. 
<li>BGPv4

BGP stands for Border Gateway Protocol. It is the only open standard
 Exterior Gateway Protocol available. BGP is a Distance Vector protocol
 which takes Autonomous System as calculation metric, instead of number 
of routers as Hop. BGPv4 is an upgrade of BGP to support IPv6 routing.</li>
</ul>
<h2>
Protocols changed to support IPv6:</h2>
<ul class="list">
<li>ICMPv6: Internet Control Message Protocol
 version 6 is an upgraded implementation of ICMP to accommodate IPv6 
requirements. This protocol is used for diagnostic functions, error and
 information message, statistical purposes. ICMPv6’s Neighbor Discovery
 Protocol replaces ARP and helps discover neighbor and routers on the 
link.</li>
<li>DHCPv6: Dynamic Host Configuration Protocol version 6 is 
an implementation of DHCP. Though IPv6 enabled hosts do not require any
 DHCPv6 Server to acquire IP address as they can be auto-configured. 
Neither do they need DHCPv6 to locate DNS server because DNS can be 
discovered and configured via ICMPv6 Neighbor Discovery Protocol. Yet 
DHCPv6 Server can be used to provide these information. </li>
<li>DNS: There has been no new version of DNS but it is now 
equipped with extensions to provide support for querying IPv6 addresses.
 A new AAAA (quad-A) record has been added to reply IPv6 query 
messages. Now DNS can reply with both IP versions (4 & 6) without 
any change in query format.</li>
</ul>
<h1>
Summary</h1>
IPv4 since 1982, has been an undisputed leader of Internet. With 
IPv4’s address space exhaustion IPv6 is now taking over the control of 
Internet, which is called Internet2. 
IPv4 is widely deployed and migration to IPv6 would not be easy. So 
far IPv6 could penetrate IPv4’s address space by less than 1%. 
The world has celebrated ‘World IPv6 Day’ on June 08, 2011 with a 
purpose to test IPv6 address over Internet in full. On June 06, 2012 
the Internet community officially launched IPv6. This day all ISPs who 
were offering IPv6 were to enable it on public domain and were to keep 
it enable. All the device manufacturer also participated to offer IPv6 
by-default enabled on devices. 
This was a step towards encouraging Internet community to migrate to IPv6. 
Organizations are provided plenty of ways to migrate from IPv4 to 
IPv6. Also organization, willing to test IPv6 before migrating 
completely can run both IPv4 and IPv6 simultaneously. Networks of 
different IP versions can communicate and user data can be tunneled to 
walk to the other side. 
<h2>
Future of IPv6</h2>
IPv6 enabled Internet version 2 will replace todays IPv4 enabled 
Internet. When Internet was launched with IPv4, developed countries 
like US and Europe took the larger space of IPv4 for deployment of 
Internet in their respective countries keeping future need in mind. But
 Internet exploded everywhere reaching and connecting every country of 
the world increasing the requirement of IPv4 address space. As a 
result, till this day US and Europe have many IPv4 address space left 
with them and countries like India and China are bound to address their 
IP space requirement by means of deployment of IPv6. 
Most of the IPv6 deployment is being done outside US, Europe. India 
and China are moving forward to change their entire space to IPv6. 
China has announced a five year deployment plan named China Next 
Generation Internet. 
After June 06, 2012 all major ISPs were shifted to IPv6 and rest of them are still moving.

IPv6 provides ample of address space and is designed to expand 
today’s Internet services. Feature-rich IPv6 enabled Internet version 2
 may deliver more than expected. 
 
<a href="http://ipv4-ipv6.blogspot.com/2014/07/ipv6-quick-guide.html">http://ipv4-ipv6.blogspot.com/2014/07/ipv6-quick-guide.html</a>

IPv6 Quick Guide

Overview Internet Protocol version 6, is a new addressing protocol designed to incorporate whole sort of requirement of future internet ...

Transition From IPv4 to IPv6

Tukiyooo 0 IPv4, IPv4/IPv6, IPv6, Transition 01:04

One problem in transition from <a href="http://ipv4-ipv6.blogspot.com/" target="_blank">IPv4 to IPv6</a> completely is that IPv6 
is not backward compatible. This results in a situation where either a 
site is on IPv6 or it is not. Unlike an implementation of new 
technology where the newer one is backward compatible so the older 
system can still work with the newer without any additional changes. 
To overcome this short-coming, there exist few technologies which can be used in slow and smooth transition from IPv4 to IPv6: 
<h2>
Dual Stack Routers</h2>
A router can be installed with both IPv4 and IPv6 addresses 
configured on its interfaces pointing to the network of relevant IP 
scheme. 
<figure>
<img caption="Dual Stack Router" src="http://www.tutorialspoint.com/ipv6/images/dual_stack_router.jpg" />
<figcaption align="center">[Image: Dual Stack Router]</figcaption>
</figure>In above diagram, a Server which is having IPv4 as well as IPv6 
address configured for it now can speak with all hosts on IPv4 network 
and IPv6 network with help of Dual Stack Router. Dual Stack Router, can
 communicate with both networks and provides a medium for hosts to 
access Server without changing their respective IP version. 
<h2>
Tunneling</h2>
In a scenario where different IP versions exist on intermediate path 
or transit network, tunneling provides a better solution where user’s 
data can pass through a non-supported IP version. 
<figure>
<img caption="Tunneling" src="http://www.tutorialspoint.com/ipv6/images/tunneling.jpg" />
<figcaption align="center">[Image: Tunneling]</figcaption>
</figure>The above diagram depicts how two remote IPv4 networks can 
communicate via Tunnel, where the transit network was on IPv6. Vice 
versa is also possible where transit network is on IPv6 and remote sites
 which intends to communicate, are on IPv4. 
<h2>
NAT Protocol Translation</h2>
This is another important method of transition to IPv6 by means of a 
NAT-PT (Network Address Translation – Protocol Translation) enabled 
device. With help of NAT-PT device, actual conversion happens between 
IPv4 and IPv6 packets and vice versa. See the diagram below: 
<figure>
<img caption="NAT-PT" src="http://www.tutorialspoint.com/ipv6/images/nat.jpg" />
<figcaption align="center">[Image: NAT - Protocol Translation]</figcaption>
</figure>

A host with IPv4 address sends a request to IPv6 enabled Server on 
Internet which does not understand IPv4 address. In this scenario, 
NAT-PT device can help them communicate. When IPv4 host sends a request
 packet to IPv6 Server, NAT-PT device/router, strips down the IPv4 
packet, removes IPv4 header and adds IPv6 header and passes it through 
the Internet. When a response from IPv6 Server comes for IPv4 host, the
 router does vice versa. 
http://ipv4-ipv6.blogspot.com/2014/07/one-problem-in-transition-from-ipv4-to.html

Transition From IPv4 to IPv6

One problem in transition from IPv4 to IPv6 completely is that IPv6 is not backward compatible. This results in a situation where either ...

What is IPv4 and IPv6 ?

Tukiyooo 0 IPv4, IPv4/IPv6, IPv6, Setup IPv6 01:02

<div class="_5pbx userContent" data-ft="{"tn":"K"}">
<a href="http://ipv4-ipv6.blogspot.com/" target="_blank">What is IPv4 and IPv6. ?</a> 
 Are you confused between IPv4 and IPv6 .Here I have listed the Differences between them. 
 IPv4 :- 1) All the addresses of IPv4 are 32 bit length 2)The support of IPsec is only Optional 3)The Senders and Forwarding Routers will do the Fragmentation 4) Broadcasts Messages are available too 5)Static of IP addresses or Dynamic configuration is required to Configure IP address 6)No Packet Flow identification 7) Internet group Management Protocol ( IGMP ) is used for the Multicast Group Membership. 
 IPv6:- 1) All the addresses of IPv4 are 128 bit length 2) Inbuilt IPsec Support 3) Only Sender will do the Fragmentation 4)) Broadcasts Messages are not available.Instead a Link local scope all nodes multi cast address is used for Broadcast 5)Auto configuration of Addresses is Available 6)Packet Flow identification is available within the IPv6 header Using the Flow Label Field 7) IGMP is replaced with the Neighbour Discovery Protocol. 
 Author: <a class="profileLink" href="https://www.facebook.com/1337vickz" rel="nofollow" target="_blank">Vicky singh</a></div>

What is IPv4 and IPv6 ?

What is IPv4 and IPv6. ? Are you confused between IPv4 and IPv6 .Here I have listed the Differences between them. IPv4 :- 1) All the ...

World IPv6 day (Test Flight)

Tukiyooo 0 IPv4/IPv6, IPv6, Setup IPv6, Test Flight 10:27

<div class="_5rgo">
<div class="msg _599f _5tfq">
<div>
Today is the 
World IPv6 day or "Test Flight" day and the goal of the Test Flight Day 
is to motivate organizations across the industry – Internet service 
providers, hardware makers, operating system vendors and web companies –
 to prepare their services for IPv6 to ensure a successful transition as
 IPv4 addresses run out. 
 
Including Google, Facebook, Yahoo!, Akamai and Limelight Networks will offer their contents over IPv6 for 24 hours. 
 
You can check your IPv6 through the <a href="http://lm.facebook.com/l.php?u=http%3A%2F%2Ftest-ipv6.com%2F&h=dAQEBlw_3&s=1" rel="nofollow" target="_blank">http://test-ipv6.com/</a>. 
 
Google has announced that if any problem occured to visit Google then they recommend to use ipv4.google.com rather using <a href="http://lm.facebook.com/l.php?u=http%3A%2F%2Fwww.google.com%2F&h=TAQEEBq0U&s=1" rel="nofollow" target="_blank">www.google.com</a> on june 8. 
 
Although
 you havent IPv6 , its not problem because they are not going to 
completly cwitch to IPv6 , They going to use both IP versions for the 
users on 8 th of june. 
 
you can read  more about google announcement from <a href="http://lm.facebook.com/l.php?u=http%3A%2F%2Fipv4.google.com%2Fsupport%2Fwebsearch%2Fbin%2Fanswer.py%3Fanswer%3D1299266%26topic%3D8995%26hl%3Den&h=LAQEDhFFy&s=1" rel="nofollow" target="_blank">ipv4.google.com/support/websearch/bin/answer.py?answer=1299266&topic=8995&hl=en</a></div>
</div>
</div>

World IPv6 day (Test Flight)

Today is the World IPv6 day or "Test Flight" day and the goal of the Test Flight Day is to motivate organizations across the ...

C++ Internet Protocol and Socket Address Classes

Tukiyooo 0 C++, Internet, IP address, IPv4, IPv4/IPv6, IPv6, Protocol, Socket 19:18

<pre>C++ Internet Protocol and Socket Address Classes

Document Number: TBD
Date: TBD
Author: Aleksandar Fabijanic <alex AT pocoproject.org>
 Günter Obiltschnig <guenter.obiltschnig AT appinf.com>

Content

1. Revision History

2. Motivation and Scope

3. IP Address
 3.1. Usage Examples
 3.1.1. IPv4
 3.1.2. IPv6
 3.2. Header <ip_address> synopsis

5. Socket Address
 5.1. Usage Examples
 5.2. Header <socket_address> synopsis

6. Conclusion

7. Acknowledgments

1. Revision History

- Oct 10 2012: created

2. Motivation and Scope

Given the pervasiveness of networking and Internet, there is a
pressing need for standard networking support in C++ language.
This proposal addresses the concerns of IP and socket addresses;
it is aimed to be one of the fundamental building blocks and
steps toward the Standard C++ Network Library goal.

This proposal is based on IP and socket address implementations
in the Net library in C++ Portable Components (POCO) [6] framework.
POCO framework has been open sourced in 2005 by its principal
sponsor (Applied Informatics Software Engineering GmbH) and is
currently licensed under Boost Software License and used in
production by numerous commercial entities as well as other
open source projects [7].

The scope of the proposal is description of functionality,
interfaces and usage examples for a set of classes providing
functionality to store and manipulate Internet Protocol
(IPv4 and v6) as well as socket (IP address + port) addresses.

3. IP Address

The ip_address class represents an Internet Protocol host
address. The address can belong to either IPv4 or IPv6 
(if the target platform supports it) address family.

Relational operators (==, !=, <, <=, >, >=) are supported. 
Notably, an IPv4 address is never equal to an IPv6 
address, even if the IPv6 address is IPv4 compatible and 
the addresses are logically the same.

For underlying IP address bit manipulation, bitwise operators
(&, |, ^, ~) are supported.

3.1 Usage Examples

3.1.1. IPv4:

ip_address ia("127.0.0.1");
assert (ia.family() == ip_address::ipv4);
assert (ia.to_string() == "127.0.0.1");
assert (ip.is_loopback());

ip_address addr("10.0.0.51");
ip_address mask(24, ip_address::ipv4);
assert(mask.prefix_len() == 24);

ip_address net = addr & mask;
assert(net.to_string() == "10.0.0.0");

ip_address host("0.0.0.51");
assert((net | host) == addr);
assert((~mask).to_string() == "0.0.0.255");

3.1.2. IPv6

ip_address ia("1080:0:0:0:8:600:200a:425c");
assert (ia.family() == ip_address::ipv6);
assert (ia.to_string() == "1080::8:600:200a:425c");

ip_address ia(62, ip_address::ipv6);
assert(ia.to_string() == "ffff:ffff:ffff:fffc::");

3.2. Header <ip_address> synopsis

namespace std {
namespace net {

typedef int socklen_t;

class ip_address {
public:
typedef std::vector<IPAddress> list;

enum family
/// Possible address families for IP addresses.
{
 ipv4
#ifdef _STD_HAVE_IPv6
 ,ipv6
#endif
};
 
ip_address();
 /// Creates a wildcard (zero) IPv4 ip_address.

ip_address(const ip_address& addr);
 /// Creates an ip_address by copying another one.

explicit IPAddress(family family);
 /// Creates a wildcard (zero) ip_address for the given address family.

explicit ip_address(const std::string& addr);
 /// Creates an IPAddress from the string containing
 /// an IP address in presentation format (dotted decimal
 /// for IPv4, hex string for IPv6).
 /// Depending on the format of addr, IPv4 or an IPv6 address is 
 /// created. See to_string() for details on the supported formats.
 /// Throws std::runtime_exception if the address cannot be parsed.

ip_address(const std::string& addr, Family family);
 /// Creates an ip_address from the string containing
 /// an IP address in presentation format (dotted decimal
 /// for IPv4, hex string for IPv6).

ip_address(const void* addr, socklen_t length);
 /// Creates an IPAddress from a native internet address.
 /// A pointer to an in_addr or an in6_addr structure may be passed.

ip_address(const void* addr, socklen_t length, uint32_t scope);
 /// Creates an IPAddress from a native internet address.
 /// A pointer to a in_addr or a in6_addr structure may be 
 /// passed. Additionally, for an IPv6 address, a scope ID
 /// may be specified. The scope ID will be ignored if an IPv4
 /// address is specified.

ip_address(uint32_t prefix, family family);
 /// Creates an ip_address mask with the given length of prefix.

ip_address(const struct sockaddr& sockaddr);
 /// Creates an ip_address from sockaddr structure.

~ip_address();
 /// Destroys the IPAddress.

ip_address& operator = (const ip_address& addr);
 /// Assigns an IPAddress.
  
void swap(ip_address& address);
 /// Swaps the IPAddress with another one.
  
family family() const;
 /// Returns the address family (ipv4 or ipv6) of the address.

uint32_t scope() const;
 /// Returns the IPv6 scope identifier of the address. Returns 0 if
 /// the address is an IPv4 address, or the address is an
 /// IPv6 address but does not have a scope identifier.

std::string to_string() const;
 /// Returns a string containing a representation of the address
 /// in presentation format.
 /// For IPv4 addresses the result will be in dotted-decimal (d.d.d.d) notation.
 /// The preferred form is x:x:x:x:x:x:x:x, where the 'x's are the hexadecimal 
 /// values of the eight 16-bit pieces of the address. This is the full form.
 /// Example: 1080:0:0:0:8:600:200a:425c
 /// It is not necessary to write the leading zeros in an individual field. 
 /// However, there must be at least one numeral in every field, except as 
 /// described below.
 /// It is common for IPv6 addresses to contain long strings of zero bits. 
 /// In order to make writing addresses containing zero bits easier, a special
  /// syntax is  available to compress the zeros. The use of "::" indicates multiple
 /// groups of 16-bits of zeros. 
 /// The "::" can only appear once in an address. The "::" can also be used to 
 /// compress the leading and/or trailing zeros in an address. 
 /// Example: 1080::8:600:200a:425c
 /// For dealing with IPv4 compatible addresses in a mixed environment,
 /// a special syntax is available: x:x:x:x:x:x:d.d.d.d, where the 'x's are the 
 /// hexadecimal values of the six high-order 16-bit pieces of the address, 
 /// and the 'd's are the decimal values of the four low-order 8-bit pieces of the 
 /// standard IPv4 representation address. Example: ::ffff:192.168.1.120
 /// If an IPv6 address contains a non-zero scope identifier, it is added
 /// to the string, delimited by a percent character. On Windows platforms,
 /// the numeric value (which specifies an interface index) is directly
 /// appended. On Unix platforms, the name of the interface corresponding
 /// to the index (interpretation of the scope identifier) is added.

bool is_wildcard() const;
 /// Returns true iff the address is a wildcard (all zero) address.
  
bool is_broadcast() const;
 /// Returns true iff the address is a broadcast address.
 /// Only IPv4 addresses can be broadcast addresses. In a broadcast
 /// address, all bits are one. For an IPv6 address, returns always false.
 
bool is_loopback() const;
 /// Returns true iff the address is a loopback address.
 /// For IPv4, the loopback address is 127.0.0.1.
 /// For IPv6, the loopback address is ::1.
 
bool is_multicast() const;
 /// Returns true iff the address is a multicast address.
 /// IPv4 multicast addresses are in the
 /// 224.0.0.0 to 239.255.255.255 range
 /// (the first four bits have the value 1110).
 /// IPv6 multicast addresses are in the
 /// FFxx:x:x:x:x:x:x:x range.
  
bool is_unicast() const;
 /// Returns true iff the address is a unicast address.
 /// An address is unicast if it is neither a wildcard,
 /// broadcast or multicast address.
  
bool is_link_local() const;
 /// Returns true iff the address is a link local unicast address.
 /// IPv4 link local addresses are in the 169.254.0.0/16 range,
 /// according to RFC 3927.
 /// IPv6 link local addresses have 1111 1110 10 as the first
 /// 10 bits, followed by 54 zeros.
  
bool is_site_local() const;
 /// Returns true iff the address is a site local unicast address.
 /// IPv4 site local addresses are in on of the 10.0.0.0/24,
 /// 192.168.0.0/16 or 172.16.0.0 to 172.31.255.255 ranges.
 /// Originally, IPv6 site-local addresses had FEC0/10 (1111 1110 11) 
 /// prefix (RFC 4291), followed by 38 zeros. Interfaces using  
 /// this mask are supported, but obsolete; RFC 4193 [3] prescribes
 /// fc00::/7 (1111 110) as local unicast prefix.
  
bool is_ipv4_compatible() const;
 /// Returns true iff the address is IPv4 compatible.
 /// For IPv4 addresses, this is always true.
 /// For IPv6, the address must be in the ::x:x range (the
 /// first 96 bits are zero).

bool is_ipv4_mapped() const;
 /// Returns true iff the address is an IPv4 mapped IPv6 address.
 /// For IPv4 addresses, this is always true.
 /// For IPv6, the address must be in the ::FFFF:x:x range.
 
bool is_well_known_mcast() const;
 /// Returns true iff the address is a well-known multicast address.
 /// For IPv4, well-known multicast addresses are in the 224.0.0.0/8 range.
 /// For IPv6, well-known multicast addresses are in the 
 /// FF0x:x:x:x:x:x:x:x range.
 
bool is_node_local_mcast() const;
 /// Returns true iff the address is a node-local multicast address.
 /// IPv4 does not support node-local addresses, thus the result is
 /// always false for an IPv4 address.
 /// For IPv6, node-local multicast addresses are in the
 /// FFx1:x:x:x:x:x:x:x range.
 
bool is_link_local_mcast() const;
 /// Returns true iff the address is a link-local multicast address.
 /// For IPv4, link-local multicast addresses are in the
 /// 224.0.0.0/24 range. Note that this overlaps with the range for well-known
 /// multicast addresses.
 /// For IPv6, link-local multicast addresses are in the
 /// FFx2:x:x:x:x:x:x:x range.

bool is_site_local_mcast() const;
 /// Returns true iff the address is a site-local multicast address.
 /// For IPv4, site local multicast addresses are in the 239.255.0.0/16 range.
 /// For IPv6, site-local multicast addresses are in the
 /// FFx5:x:x:x:x:x:x:x range.

bool is_org_local_mcast() const;
 /// Returns true iff the address is a organization-local multicast address.
 /// For IPv4, organization-local multicast addresses are in the
 /// 239.192.0.0/16 range.
 /// For IPv6, organization-local multicast addresses are in the
 /// FFx8:x:x:x:x:x:x:x range.

bool is_global_mcast() const;
 /// Returns true iff the address is a global multicast address.
 /// For IPv4, global multicast addresses are in the 
 /// 224.0.1.0 to 238.255.255.255 range.
 /// For IPv6, global multicast addresses are in the
 /// FFxF:x:x:x:x:x:x:x range.
 
bool operator == (const ip_address& addr) const;
 /// Returns true if IP addresses are equal.

bool operator != (const ip_address& addr) const;
 /// Returns true if IP addresses are not equal.

bool operator < (const ip_address& addr) const;
 /// Returns true if this IP address is lesser than addr.

bool operator <= (const ip_address& addr) const;
 /// Returns true if this IP address is lesser than or equal to addr.

bool operator >  (const ip_address& addr) const
 /// Returns true if this IP address is greater than addr.

bool operator >= (const ip_address& addr) const;
 /// Returns true if this IP address is greater than or equal to addr.

ip_address operator & (const ip_address& addr) const;
 /// Performs a bitwise ANd operation and returns result.

ip_address operator | (const ip_address& addr) const;
 /// Performs a bitwise OR operation and returns result.

ip_address operator ^ (const ip_address& addr) const;
 /// Performs a bitwise XOR operation and returns result.

ip_address operator ~ () const;
 /// Performs a bitwise NOT operation on this IP address and returns result.
  
socklen_t length() const;
 /// Returns the length in bytes of the internal socket address structure. 
  
const void* addr() const;
 /// Returns the internal address structure.
  
uint32_t af() const;
 /// Returns the address family (AF_INET or AF_INET6) of the address.

unit32_t prefix_len() const;
 /// Returns the prefix length.
  
void mask(const ip_address& mask);
 /// Masks the IP address using the given netmask, which is usually
 /// a IPv4 subnet mask. Only supported for IPv4 addresses.
 /// The new address is (address & mask).
  
void mask(const ip_address& mask, const ip_address& set);
 /// Masks the IP address using the given netmask, which is usually
 /// a IPv4 subnet mask. Only supported for IPv4 addresses.
 /// The new address is (address & mask) | (set & ~mask).
  
static ip_address assign(const std::string& addr);
 /// Creates an IPAddress from the string containing
 /// an IP address in presentation format (dotted decimal
 /// for IPv4, hex string for IPv6).
 /// Depending on the format of addr, either an IPv4 or
 /// an IPv6 address is created.
 /// See to_string() for details on the supported formats.
 /// Throws std::runtime_exception if the address cannot be parsed.

static bool try_assign(const std::string& addr, IPAddress& result);
 /// Tries to interpret the given address string as an
 /// IP address in presentation format (dotted decimal
 /// for IPv4, hex string for IPv6).
 /// Returns true and stores the IPAddress in result if the
 /// string contains a valid address.
 /// Returns false and leaves result unchanged otherwise.

static IPAddress wildcard(Family family = ipv4);
 /// Returns a wildcard IPv4 or IPv6 address.
  
static IPAddress broadcast();
 /// Returns a broadcast IPv4 address (255.255.255.255).
};
}} // namespace std::net

4. Socket Address

This class represents an internet (IP) endpoint/socket address. The address
can belong either to the IPv4 or the IPv6 address family and consists of a
host IP  address and a port number.

4.1 Usage Examples

socket_address wild;
assert (wild.host().is_wildcard());
assert (wild.port() == 0);

socket_address sa1("192.168.1.100", 100);
assert (sa1.host().to_string() == "192.168.1.100");
assert (sa1.port() == 100);

socket_address sa2("192.168.1.100", "100");
assert (sa2.host().to_string() == "192.168.1.100");
assert (sa2.port() == 100);

socket_address sa3("192.168.1.100", "ftp");
assert (sa3.host().to_string() == "192.168.1.100");
assert (sa3.port() == 21);

socket_address sa4("www.appinf.com", 80);
assert (sa4.host().toString() == "50.57.108.29");
assert (sa4.port() == 80);

4.2 Header <socket_address> synopsis

namespace std {
namespace net {
class socket_address
 /// This class represents an (IP) socket address.
 /// The address can belong either to the IPv4 or the IPv6 address
 /// family and consists of a host address and a port number.
{
public:
socket_address();
 /// Creates a wildcard (all zero) IPv4 socket_address.

socket_address(const ip_address& host, uint_16t port);
 /// Creates a socket_address from an IP address and a port number.

socket_address(const std::string& host, uint_16t port);
 /// Creates a socket_address from an IP address and a port number.
 /// The IP address must either be a domain name, or it must
 /// be in dotted decimal (IPv4) or hex string (IPv6) format.

socket_address(const std::string& host, const std::string& port);
 /// Creates a socket_address from an IP address and a
 /// service name or port number.
 /// The IP address must either be a domain name, or it must
 /// be in dotted decimal (IPv4) or hex string (IPv6) format.
 /// The given port must either be a decimal port number, or
 /// a service name (as typically returned in struct servent
 /// by the getservbyname() call.

explicit socket_address(const std::string& host_and_port);
 /// Creates a socket_address from an IP address or host name and a
 /// port number/service name. Host name/address and port number
 /// must be separated by a colon. In case of an IPv6 address, the
 /// address part must be enclosed in brackets.
 /// 
 /// Examples:
 ///     192.168.1.10:80
 ///     [::ffff:192.168.1.120]:2040
 ///     www.appinf.com:8080

socket_address(const socket_address& addr);
 /// Creates a socket_address by copying another one.

socket_address(const struct sockaddr* addr, socklen_t length);
 /// Creates a socket_address from a native socket address.

~socket_address();
 /// Destroys the socket_address.

socket_address& operator = (const socket_address& addr);
 /// Assigns another socket_address.

void swap(socket_address& addr);
 /// Swaps the socket_address with another one.

ip_address host() const;
 /// Returns the host IP address.

uint_16t port() const;
 /// Returns the port number.

socklen_t length() const;
 /// Returns the length of the internal native socket address.

const struct sockaddr* addr() const;
 /// Returns a pointer to the internal native socket address.

uint32_t af() const;
 /// Returns the address family (AF_INET or AF_INET6) of the address.

std::string to_string() const;
 /// Returns a string representation of the address.

ip_address::family family() const;
 /// Returns the address family of the host's address.

bool operator < (const socket_address& addr) const;
 /// Less than operator.

bool operator == (const socket_address& addr) const;
 /// Equal operator.

bool operator != (const socket_address& addr) const;
 /// Not equal operator.

};
}} // namespace std::net

6. Conclusion

Class interfaces for IP and socket address as well as rationale for their 
introduction in C++ Standard and usage examples were described in this 
proposal. This proposal is one of the starting points and building blocks 
for C++ Standard Networking Library. Implementation of the described 
functionality is currently available in POCO framework [6]; the 
implementation differs in naming scheme from this proposal. Given a 
positive feedback on the proposal, implementation  will be available 
in the near future as a standalone implementation in standard-compliant 
naming convention, with accompanying tests and code examples.

7. Acknowledgements

POCO original author (Günter Obiltschnig)
POCO project contributors and users

References

[1] RFC 791
[2] RFC 2460
[3] RFC 4193
[4] RFC 3513
[5] RFC 3879
[6] C++ Portable Components: http://pocoproject.org
[7] List of known POCO users: http://pocoproject.org/forum/viewtopic.php?f=11&t=3826

C++ Internet Protocol and Socket Address Classes

C++ Internet Protocol and Socket Address Classes Document Number: TBD Date: TBD Author: Aleksandar Fabijanic <alex AT pocoproject.or...

What is tunneltrace?

Tukiyooo 0 Internet Protocol Version4 and IPv6, IPv4/IPv6, protocolos DNS (sistema de nombre de dominio) en linux y en windows protocolos DNS, tunnels, tunneltrace 19:15

TUNNELTRACE-RS v1.0                                =================== What is tunneltrace? -------------------- Tunneltrace is a tool used for detecting IPv6 in IPv4 tunnels. More precisely, Tunneltrace can run in 2 modes: Mode 1:   Given two IPv4 Addresses it checks if there is a tunnel between them. If there is evidence of the presence of a tunnel, tunneltrace outputs a confidence value, which provides a measure of the probability that the tunnel exists, and tries to determine the IPv6 addresses of the endpoints. Mode 2:   Tunneltrace can also determine, given an IPv6 Address, the full Path from the node where tunneltrace is launched to the given address. From the Path determined tunneltrace identifies the Path MTU and all the tunnels inside the path, and for each tunnel found it tries to find the IPv4 addresses of the endpoints and outputs a confidence value. Techniques used --------------- Tunneltrace uses three techniques to detect tunnels: 1) IPv4 spoofing 2) DNS lookups 3) Queries to the 6bone registry Each of the above techniques has a degree of confidence. The confidence value output by tunneltrace is the sum of the confidence values of each technique that succeeded. Brief description of the techniques ----------------------------------- 1. IPv4 spoofing These are the main techniques used by tunneltrace. By encapsulating an IPv6 packet in an IPv4 packet having the source address of one of the tunnel endpoints, tunneltrace can trick the other endpoint into treating the packet as if it had come from the tunnel. Tunneltrace uses four spoofing techniques:     a) Injected Ping        Encapsulated IPv6 echo request to a pingable IPv6 interface. Used to        determine if there is a tunnel.     b) Dying Packet        Similar to the above, but injects packets with a Hop Count field of 1.        Used to determine the IPv6 addresses of the tunnel endpoints.     c) Ping Pong Packet        Similar to the above, but attempts to determine the address of one        endpoint if the address of the other endpoint is known.     d) Fragmented Injection        As Injected Ping but puts the IPv6 echo request message into three IPv4 fragments 2. DNS Lookups Looks for AAAA records with the endpoint hostnames, if we are running tunneltrace in mode 1. Looks for A records with the endpoint hostnames (retreived by a reverse-lookup),if we are running tunneltrace in mode 2. 3. Queries to the 6bone registry Looks for a corresponding entry in the 6bone registries. Tunneltrace requires a copy of the 6bone registry file to be stored locally in /etc/6bone.db or in the directory where tunneltrace is installed. You may download this file from ftp://whois.6bone.net/6bone/6bone.db.gz A detailed description of the techniques used can be found in the papers available at the URL: http://www.dia.uniroma3.it/~compunet/tunneldiscovery/tunneling-noms.pdf 4) Path MTU Discovery Tunneltrace tries to send ICMPv6 packets with the MTU of the node where it is running and using Hop Limit manipulation for determining the Path (Modifing the HL field). If it receives a ICMPv6 message of Packet-Too-Big, from that point on it will send packets with the MTU specified in the Packet-Too-Big messagge, until it doesn't receive antoher packet too big messagge, and so on. 5) Fragmented IPv6 in IPv4 Path MTU Discovery If Tunneltrace finds on its Path a Tunnel, it tryes to use the outern endpoint of it as Vantage Point for Path MTU Discovery , by creating an IPv6 Packet of the MTU of the source node in IPv4 Fragments of 68 bytes. So to be able to do Path MTU Discovery (and PATH TRACING with Hop Limit manipulation) from the Vantage Point. This repeatably for every new Vantage Point that Tunneltrace finds further on in the Path. How confidence values are calculated ------------------------------------ The Confidence value output by tunneltrace is calculated using the following criteria: Spoofing Techniques ->   Injected Ping success on 1 Endpoint only  : 5 Confidence Points    Injected Ping success of both Endpoints   : 7 Confidence Points   Dying Packet success on each Endpoint     : 1 Confidence point   Ping Pong Packet success on one Endpoint (if Dying Packet didn't work)                                             : 1 Confidence point If Spoofing Techniques succeeded, then ->   6bone registries lookup success           : 1 Confidence points If no Spoofing Technique succeeded, then ->   DNS lookups success                             : 1 Confidence points   6bone registries lookup success           : 4 Confidence points Compiling tunneltrace --------------------- To compile tunneltrace, run the build.sh script in the distribution. Compilation requires the C++ development libraries to be installed. Tunneltrace is known to compile on Linux and FreeBSD, but should also compile and run on other platforms such as Solaris. Tunneltrace runs on both littleEndian and bigEndian machines. Using tunneltrace ----------------- 1. Prerequisites Due to the use of spoofing techniques that require raw sockets, you must be root to run tunneltrace. Some of the techniques used by tunneltrace require a reference IPv6 address. This address must be globally routed or, at a minimum, reachable from the tunnel endpoints. The reference IPv6 address may be specified on the command line using the -h parameter or in the file /etc/tunneltrace.ip. As stated previously, tunneltrace also requires a 6bone registry dump in the file /etc/6bone.db or in the directory where tunneltrace is installed. You may run multiple istances of tunneltrace in parallel, since each one recognizes its own packets. 2. Usage Tunneltrace's syntax is the following : Mode 1: tunneltrace [ -h reference IPv6 ] [ -v ] <source IPv4> <dest IPv4>     Where <source IPv4> AND <dest IPv4>: IPv4 addresses or hostnames Mode 2: tunneltrace [ -h reference IPv6 ] <dest IPv6>     Where <dest IPv6>: IPv6 address or hostname Tunneltrace exits with an error if <source IPv4> or <dest IPv4> are not valid IPv4 addresses or resolvable hostnames or if the reference IPv6 is not a valid IPv6 address or <dest IPv6> is not a valid IPv6 address or resolvable hostname or is not reachable. The -v option is used for generating Parametric OUTPUT (on one line) in order to see the techniques that worked in detail Output format ------------- The output format of tunneltrace is the following: Mode 1: # tunneltrace <source IPv4> <dest IPv4> source_host(source_IPv4) -> dest_host(dest_IPv4) source_IPv6 -> dest_IPv6 ; CONFIDENCE X/10 Mode 2: # tunneltrace <dest IPv6> 1         host_1(IPv6_1)  MTU 2         host_2(IPv6_2)  MTU source_host1(source_IPv4_1) -> dest_host2(dest_IPv4_2) source_IPv6_1 -> dest_IPv6_2 ; CONFIDENCE X/10 3         host_3(IPv6_3)  MTU . . 8         host_dest(IPv6_dest)  MTU If none of the techniques worked, tunneltrace will output a confidence value of zero and one or both of the IPv6 addresses will be shown as "unknown". Credits ------- Tunneltrace was developed as part of Davide De Micco's master thesis in collaboration with the Computer Networks research group at Roma Tre University. Contributors are: Davide De Micco Lorenzo Colitti Giuseppe Di Battista Emanuele Conti Maurizio Patrignani

What is tunneltrace?

TUNNELTRACE-RS v1.0 =================== What is tunneltrace? -----------------...

How to add IPv6 over IPv4 support to your network behind a NAT router

Tukiyooo 0 IPv4, IPv4/IPv6, IPv6, router, Setup IPv6 19:12

<pre>Firewall+IPv6 Tunnel mini-HOWTO
Hernán Freschi <hjf(at)hjf.com.ar>
version 0.1, 2002-11-27

How to add IPv6 over IPv4 support to your network behind a NAT router.
----------------------------------------------------------------------

Table of Contents

1. Introduction

1.1 Copyright
     1.2 Disclaimer
     1.3 Credits
     1.4 Changelog
  
  2. What's IPv6? What can it do for me?

3. How do I connect to the 6bone?

4. What should I allow through the firewall?

5. Configuring the IPv6 machines/routers

5.1. Linux

5.2. Windows

5.2.1 IPv6 stand-alone machine
    5.2.2 IPv6 network
      5.2.2.1 The Router
      5.2.2.2 The clients

6. Examples
     6.1 Windows PC using IPv6, behind iptables NAT/MASQ, with a tunnel from HE.
     6.2 Multiple Windows PCs using IPv6, behind iptables NAT/MASQ, with a tunnel from BTExact.

----------------------------------------------------------------------

1. Introduction

1.1 Copyright

This document is Copyright 2002 by Hernán Freschi. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.1 or any later version published by the Free Software Foundation with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license can be found at www.gnu.org.

1.2 Disclaimer 
Use the information in this document at your own risk. I disavow any potential liability for the contents of this document. Use of the concepts, examples, and/or other content of this document is entirely at your own risk.

All copyrights are owned by their owners, unless specifically noted otherwise. Use of a term in this document should not be regarded as affecting the validity of any trademark or service mark.

Naming of particular products or brands should not be seen as endorsements.

You are strongly recommended to take a backup of your system before major installation and backups at regular intervals.

1.3 Credits

Hernán Freschi <hjf(at)hjf.com.ar>

Microsoft, Windows, 2000, XP, SP1, .NET Server 2003 are all trademarks of Microsoft Corp.

Any comments or suggestions can be mailed to my mail address on: hjf(at)hjf.com.ar

This document is still in beta phase, so errors and omissions may be present.

1.4 Changelog

0.1 Initial Release.

Getting Started

2. What's IPv6? What can it do for me?

Sorry, that is beyond the scope of this document. This aims to make a iptables firewall to allow incoming traffic from an IPv6 tunnel.

3. How do I connect to the 6bone?

Through a tunnel broker!. Get your account (for free) at:

www.tunnelbroker.net (USA)
tb.ipv6.btexact.com (UK)
tb.ngnet.it (Italy?)

You could also use www.freenet6.net, but they use proprietary software, which doesn't run inside a network. But it's easier to implement and even assigns /48 subnets.

4. What should I allow through the firewall?

Everything that comes from the tunnel address, except ICMP (what for? let the linux box answer, so the packets dont get in the network). The rules I use are this:

iptables -A FORWARD -s <tunnel address> -p ! ICMP -i eth0 -j ACCEPT
iptables -t nat -A PREROUTING -i eth0 -j DNAT --to <internal router address>

And that's it. The outgoing packets don't need special treatment.

Note: This, of course, assumes that your Linux firewall doesn't handle the IPv6 packets. It's designed to run on tiny distros like FloppyFW (www.zelow.no/floppyfw) or LRP (www.lrp.org). With this, the firewall doesn't need support for IPv6. These packets are handled in an internal, more powerful (ie: with a hard disk) computer.

5. Configuring the IPv6 machines/routers

5.1 Linux

I don't have a linux box to experiment, you can either
a) Donate a hard disk, so I can install linux again or
b) Write this section for me :)

5.2 Windows (2000/XP/XP-SP1/.NET Server 2003 ONLY! Win9x is UNSUPPORTED).

First of all, you have to install IPv6 support:

C:\> ipv6 install
Installing...

Success.

5.2.1 IPv6 stand-alone machine:

Use your brokers script! If they didn't provide one, use these:

ipv6.exe rtu ::/0 2/::<tunnel address>
ipv6.exe adu 2/<your ipv6 address>

The 2/ is the Interface Index. It's usually 2, but it may vary. If in doubt, type

ipv6 if

and look for a line like this:

Interface 2: Automatic tunnel pseudo-interface

The number, obviously, is the one you are looking for.

5.2.2 IPv6 network

(Note: this applies only to the external network. If you need help setting up the IPv6 lan, read www.microsoft.com/ipv6)

5.2.2.1 The Router

Use your brokers script! If they didn't provide one, use these:

ipv6.exe rtu ::/0 2/::<tunnel address>
ipv6.exe adu 2/<your ipv6 address>
ipv6.exe rtu <your ipv6 subnet>/<your ipv6 netmask> 4 pub life 86400
ipv6.exe ifc 2 forw
ipv6.exe ifc 3 forw
ipv6.exe ifc 4 forw adv

2, 3, 4 are the interface indices. They may vary. To find out, type

ipv6 if

5.2.2.2 The clients

You don't need to do nothing, they are auto configured.

6. Examples:

6.1 Windows PC using IPv6, behind iptables NAT/MASQ, with a tunnel from HE.

Equipment required:
1 Box capable of running iptables (kernel = 2.4.x)
1 Box running Microsoft® Windows 2000, Windows XP (SP1), Windows .NET Server 2003.

Tunnel:
1 /127 Allocation from Hurricane Electric

+---+ +---+ \/\/\/\/\/ +------+ /\/\/\/\/\
 |WIN|------------|FFW|-----------/INTERNET\---------|TUNNEL|----------\ 6bone /
 +---+ +---+ \/\/\/\/\/ +------+ /\/\/\/\/\
10.42.42.100<->10.42.42.1 <-> 209.13.122.2 <-> ipv6.he.net <-> 2001:470:1F00:FFFF::xxxx

Configuration:
On the Linux box type:

iptables -A FORWARD -s 64.71.128.82 -p ! ICMP -i eth0 -j ACCEPT
iptables -t nat -A PREROUTING -s 64.71.128.82 -i eth0 -j DNAT --to 10.42.42.100

On the MS box type:

ipv6 rtu ::/0 2/::64.71.128.82 pub
ipv6 adu 2/2001:470:1F00:FFFF::xxxx

Congratulations. You are set.

Now try pinging to 6bone.net, for example.

6.2 Multiple Windows PCs using IPv6, behind iptables NAT/MASQ, with a tunnel from BTExact.

Equipment required:
1 Box capable of running iptables (kernel = 2.4.x)
n Boxes running Microsoft® Windows 2000, Windows XP (SP1), Windows .NET Server 2003.

Tunnel:
1 /64 Allocation from Hurricane Electric

+---+ +---+ +---+
  |WIN| |WIN| |WIN|
  +---+ +---+ +---+
    +-----+-----+
  +---+            +---+           \/\/\/\/\/         +------+          /\/\/\/\/\
--|WRT|------------|FFW|-----------/INTERNET\---------|TUNNEL|----------\  6bone /
  +---+            +---+           \/\/\/\/\/         +------+          /\/\/\/\/\

10.42.42.100<->10.42.42.1 <-> 209.13.122.2 <-> 193.113.58.80 <-> 2001:618:400::xxxx:xxxx

Configuration:
On the Linux box type:

iptables -A FORWARD -s 64.71.128.82 -p ! ICMP -i eth0 -j ACCEPT
iptables -t nat -A PREROUTING -s 64.71.128.82 -i eth0 -j DNAT --to 10.42.42.100

On the MS router type:

ipv6.exe rtu ::/0 2/::193.113.58.80
ipv6.exe adu 2/2001:618:400::xxxx:xxxx
ipv6.exe rtu 2001:618:400:xxxx::/64 4 pub life 86400
ipv6.exe ifc 2 forw
ipv6.exe ifc 3 forw
ipv6.exe ifc 4 forw adv

On the other machines type:

Nothing, they are auto configured. If they dont work, try:

ipv6 reset

If that doesn't work, check for a default route (::/0).

ipv6 rt

If there isn't one, try adding one:

ipv6 rtu ::/0 n/(your routers ipv6 address)

(where n is the interface index of the ethernet board connected to the network, usually 4).

If it works, but the next time you reboot, it does not auto configure, then maybe you are not publishing the default route in the router.

Congratulations. You are set.

Now try pinging to 6bone.net, for example. 
</pre>

How to add IPv6 over IPv4 support to your network behind a NAT router

Firewall+IPv6 Tunnel mini-HOWTO Hernán Freschi <hjf(at)hjf.com.ar> version 0.1, 2002-11-27 How to add IPv6 over IPv4 support to your ...

Converting IPv4 addresses to IPv6 addresses

Tukiyooo 0 Converting, Easy Explanation Of IPv4, Internet Protocol Version4 and IPv6, IPv4, IPv4/IPv6, Setup IPv6 19:08

Converting IPv4 addresses to IPv6 addresses
 
-------------------------------------------
 
Here's a cool tool for doing it in windows:
 
<a href="http://www.softpedia.com/get/network-tools/ip-tools/ipconvert.shtml" rel="nofollow">http://www.softpedia.com/get/Network-Tools/IP-Tools/IPConvert.shtml</a>

Here's the main ipv6 website:

There's a good read at Microsfoft on tcp/ip
 
fundamentals and subnetting:

<a href="http://www.microsoft.com/technet/itsolutions/network/evaluate/" rel="nofollow">http://www.microsoft.com/technet/itsolutions/network/evaluate/</a>
 
technol/tcpipfund/tcpipfund_ch04.mspx#EEIAG

Here are some OpenBSD related sites:

<a href="http://www.inet6.dk/config/openbsd.html" rel="nofollow">http://www.inet6.dk/config/openbsd.html</a>
 
<a href="http://www.sans.org/reading_room/whitepapers/firewalls/807.php" rel="nofollow">http://www.sans.org/reading_room/whitepapers/firewalls/807.php</a>

I'm sure there are scads more. Google is your friend! ;)

Here are a few more, more general or linux:

<a href="http://enterprisenetworkingplanet.com/netsp/article.php/3634596" rel="nofollow">http://enterprisenetworkingplanet.com/netsp/article.php/3634596</a>
 
<a href="http://enterprisenetworkingplanet.com/netsp/article.php/3629546" rel="nofollow">http://enterprisenetworkingplanet.com/netsp/article.php/3629546</a>
 
<a href="http://enterprisenetworkingplanet.com/netsp/article.php/3633211" rel="nofollow">http://enterprisenetworkingplanet.com/netsp/article.php/3633211</a>

The examples below are pretty simple Class C
 
network examples. I put several sequential
 
addresses in order to show the progression
 
in IPv6 notation.

--------------------------------------------
 
IPV4 Address: 192.168.1.100

IPV6 Address:

IPv6 Full Address
 
0000:0000:0000:0000:0000:0000:C0A8:0164

IPv6 Shorthand Adress:
 
::C0A8:0164

IPv6 & Dot Notation Full Address:
 
0000:0000:0000:0000:0000:0000:192.168.1.100

IPv6 & Dot Notation Shorthand Adress:
 
192.168.1.100
 
--------------------------------------------

--------------------------------------------
 
IPV4 Address: 192.168.1.101

IPV6 Address:

IPv6 Full Address
 
0000:0000:0000:0000:0000:0000:C0A8:0165

IPv6 Shorthand Adress:
 
::C0A8:0165

IPv6 & Dot Notation Full Address:
 
0000:0000:0000:0000:0000:0000:192.168.1.101

IPv6 & Dot Notation Shorthand Adress:
 
192.168.1.101
 
--------------------------------------------

--------------------------------------------
 
IPV4 Address: 192.168.1.102

IPV6 Address:

IPv6 Full Address
 
0000:0000:0000:0000:0000:0000:C0A8:0166

IPv6 Shorthand Adress:
 
::C0A8:0166

IPv6 & Dot Notation Full Address:
 
0000:0000:0000:0000:0000:0000:192.168.1.102

IPv6 & Dot Notation Shorthand Adress:
 
192.168.1.102
 
--------------------------------------------

--------------------------------------------
 
IPV4 Address: 192.168.1.103

IPV6 Address:

IPv6 Full Address
 
0000:0000:0000:0000:0000:0000:C0A8:0167

IPv6 Shorthand Adress:
 
::C0A8:0167

IPv6 & Dot Notation Full Address:
 
0000:0000:0000:0000:0000:0000:192.168.1.103

IPv6 & Dot Notation Shorthand Adress:
 
192.168.1.103
 
--------------------------------------------

--------------------------------------------
 
IPV4 Address: 192.168.1.104

IPV6 Address:

IPv6 Full Address
 
0000:0000:0000:0000:0000:0000:C0A8:0168

IPv6 Shorthand Adress:
 
::C0A8:0168

IPv6 & Dot Notation Full Address:
 
0000:0000:0000:0000:0000:0000:192.168.1.104

IPv6 & Dot Notation Shorthand Adress:
 
192.168.1.104
 
----------------------

Converting IPv4 addresses to IPv6 addresses

Converting IPv4 addresses to IPv6 addresses ------------------------------------------- Here's a cool tool for doing it in windows: h...

A Communication Mechanism between IPv4 and IPv6

Tukiyooo 0 Communication, Internet Protocol Version4 and IPv6, IPv4, IPv4/IPv6 19:02

<pre>Expires in six month K. Watanabe, Hitachi
 Y. Atarashi, Hitachi
 T. Miyamoto, Hitachi
 K. Yamamoto, NAIST
 J. Murai, Keio University

A Communication Mechanism between IPv4 and IPv6

<draft-tsuchiya-ipv4-ipv6-translator-00.txt>

Status of this Memo

This document is an Internet-Draft. Internet-Drafts are working
    documents of the Internet Engineering Task Force (IETF), its areas,
    and its working groups. Note that other groups may also distribute
    working documents as Internet-Drafts.

Internet-Drafts are draft documents valid for a maximum of six
    months and may be updated, replaced, or obsoleted by other documents
    at any time.  It is inappropriate to use Internet-Drafts as
    reference material or to cite them other than as ``work in
    progress.''

To learn the current status of any Internet-Draft, please check the
    ``1id-abstracts.txt'' listing contained in the Internet-Drafts
    Shadow Directories on ds.internic.net (US East Coast), nic.nordu.net
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    Rim).

Abstract

In the late stage of the transition from IPv4 to IPv6, IPv4 lands
    are interconnected by IPv6 ocean and it is necessary for an IPv4
    node and an IPv6 to communicate directly. This memo proposes a
    mechanism to enable such direct communication with extension name
    servers, an address mapper, and translators for each IPv4 land.

1. Introduction

RFC1933 [TRANS-MECH] proposed mechanisms to transit IPv4 [IPv4] to
    IPv6 [IPv6], including dual stack and tunneling, for the early
    stage. IPv6 nodes are assumed to have IPv4 stack and IPv4 addresses.
    In the late stage of the transition, however, the space of IPv4

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INTERNET-DRAFT                                           November 1997

address will be exhausted. So, an IPv4 address cannot be assigned to
    dual-stack hosts. Moreover, IPv6-only hosts will appear for cost
    reasons. It is expected that IPv4 hosts will retain for a long time,
    even after appearance of IPv6-only hosts. Therefore, it is highly
    desired to develop a mechanism to enable a communication between an
    IPv4 host and an IPv6 host directly.

Though a header conversion mechanism is defined in [HDRCNV],
    interaction for an IPv4 host, an IPv6 host, a header conversion
    router, and name servers is not mentioned. This memo describes an
    entire scheme of direct communications between IPv4 hosts and IPv6
    hosts. The scheme is applicable to environments where there are
    multiple name servers and multiple site boundary routes thanks to
    one "address mapper".  It is not necessary to modify IPv4 hosts and
    IPv6 hosts.

This document uses the words defined in [IPV4], [IPV6], and
    [TRANS-MECH].

2. Components

In the late stage of the transition, IPv4 "land"s are interconnected
    by IPv6 "ocean". A set of IPv4-only nodes in an organization is an
    example of IPv6 island.

The proposed system consists of extension name servers, one address
    mapper, and translators. To implement communication between IPv4
    nodes and IPv6 nodes, each IPv4 island needs to install such
    components.

Extension name servers have both IPv4 stack and IPv6 stack and
    provides name service to IPv4 nodes and IPv6 nodes. Translators also
    have dual-stack functionality and translates "language" of IPv4
    nodes and that of IPv6 nodes. The address mapper is communicates
    only with the extension name servers and the translators.

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INTERNET-DRAFT                                           November 1997

Figure 1 illustrates an IPv4 land which installed the proposed
    system.

+---------+                                +-------- //
      |IPv4 node|                                |
      +----+----+                                |
           |                                     |
    +------+------+                              |
    |             |                              |
    |An IPv4 land |                              | IPv6 ocean
    |             |                              |
    |             |  +------------------------+  |         +---------+
    |             +--+ extension name servers +--+         |IPv6 node|
    |             |  +------------+-----------+  |         +---------+
    |             |               |              |
    |             |  +------------+-----------+  |         +---------+
    |             |  |   one address mapper   |  |         |IPv6 node|
    |             |  +------------+-----------+  |         +---------+
    |             |               |              |
    |             |  +------------+-----------+  |         +---------+
    |             +--+       translators      +--+         |IPv6 node|
    |             |  +------------------------+  |         +---------+
    |             |                              |
    +------+------+                              |
           |                                     |
      +----+----+                                |
      |IPv4 node|                                +-------- //
      +---------+

Figure 1

2.1 Translator between IPv4 and IPv6

The followings are examples of Translator between IPv4 and IPv6.

(1) Proxy gateway

An proxy gateway locates between an IPv4 host and an IPv6 host
        and establishes both an IPv4 connection to the IPv4 host and an
        IPv6 connection to the IPv6 host. The proxy gateway relays data
        from the IPv4 host to the IPv6 host and vice versa.

(2) Header conversion router

A header conversion router locates between an IPv4 host and an

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INTERNET-DRAFT                                           November 1997

IPv6 host. When the router receives an IPv4 packet, the router
        converts its IPv4 header to an IPv6 header then forwards it.
        When the router receives an IPv6 packet, the router converts its
        IPv6 header to an IPv4 header then fragments the packet if
        necessary and forwards it.

2.2 Extension Name Server

Extension name servers returns a "proper" answer in a response to
    IPv4 node's request or IPv6 node's request.

An IPv4 node typically requests one of extension name servers to
    resolve 'A' record correspond to a host name. If 'A' record is
    resolved, the server returns it. If only 'AAAA' record is available,
    the server requests an address mapper to assign one IPv4 address
    correspond to its IPv6 address. Then the server returns the assigned
    IPv4 address to the IPv4 node.

An IPv6 node typically requests one of extension name servers to
    resolve 'AAAA' record correspond to a host name. If 'AAAA' record is
    resolved, the server returns it. If only 'A' record is available,
    the server requests the address mapper to assign one IPv6 address
    correspond to its IPv4 address. Then the server returns the assigned
    IPv6 address to IPv6 node.

2.3 Address Mapper

An address mapper maintains an IPv4 address spool and an IPv6
    address spool. An example of the IPv4 address spool is private
    addresses(e.g number 10). An example of the IPv6 address spool is a
    part of IPv6 space assigned to the organization where the IPv4 land
    locates inside.

When an extension name server or a translator requests one IPv6
    address for an IPv4 address, the address mapper selects one IPv6
    address from the IPv6 address spool and returns it.

When an extension name server or a translator requests one IPv4
    address for an IPv6 address, the address mapper selects one IPv4
    address from the IPv4 address spool and returns it.

3. Interaction Examples

The following subsection explains communication from an IPv4 node to
    an IPv6 node and communication from an IPv6 node to an IPv4 node,
    respectively.

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INTERNET-DRAFT                                           November 1997

3.1 Communication from an IPv4 node to an IPv6 node

This subsection describes communication between an IPv4 node called
    "host4" and an IPv6 node called "host6". The communication is
    triggered by "host4".

"host4" sends a query to an extension name server to resolves 'A'
    record for "host6".

The extension name server tries resolving both 'A' record and 'AAAA'
    record for "host6" but only 'AAAA' record is resolved. Then the
    server requests an address mapper to assign one IPv4 address
    correspond to the IPv6 address.

The address mapper selects one IPv4 address out of its IPv4 address
    spool and returns it to the server.

The server creates 'A' record for the assigned IPv4 address and
    returns it to "host4".

"host4" sends IPv4 data to "host6".

The IPv4 data reaches a translator. The translator tries translating
    the IPv4 data to IPv6 data but does not know how to translate. (For
    example, a proxy gateway cannot create an IPv6 connection to "host6"
    since the IPv6 address of "host6" is not available.)  So, the
    translator requests the mapper to tell mapping entries for the IPv4
    source address and the IPv4 destination address.

The mapper looks up its mapping table with the IPv4 destination
    address and finds one IPv6 address for it. Then the mapper looks up
    its mapping table with the IPv4 source address. In this case, there
    is not a mapping entry so the mapper selects one IPv6 address for
    the IPv4 source address. Finally, the mapper returns a pair of the
    IPv6 source address and the IPv6 destination address to the
    translator.

The translator translates the IPv4 data to IPv6 data. (For example,
    the proxy gateway creates one IPv6 connection to "host6" and relay
    the IPv4 data.)

The IPv6 data reaches "host6". "host6" sends new IPv6 data to
    "host4".

The IPv6 data reaches the translator. This time the translator has
    mapping entries for the IPv6 source address and the IPv6 destination

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INTERNET-DRAFT                                           November 1997

address. The translator translates the IPv6 data to IPv4 data. (For
    example, the proxy gateway just relays the data.)

The IPv4 data reaches "host4".

The following diagram illustrates the interaction above:

IPv4    extension      address    translator    IPv6
        node    name server    mapper                   node
        "host4"                                         "host6"

Resolve an IPv4 address for host6

---> Query of 'A' record for "host6".

only 'AAAA' record is resolved.

---> Request one IPv4 address correspond to
                                the IPv6 address.

Assign on IPv4 address.

<--- Reply with the IPv4 address.

Create 'A' record for the IPv4 address.

<--- Reply with the 'A' record.

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INTERNET-DRAFT                                           November 1997

IPv4    extension      address    translator    IPv6
        node    name server    mapper                   node
        "host4"                                         "host6"

Send data to host6

=============================> IPv4 data

Try translating but don't
                                          know how to translate it.

<--- Request IPv6 addresses
 corresond to the IPv4 source
 address and to the IPv4
 destination address.

One IPv6 address correspond to the IPv4
                                destination address is already
                                available. Assign one IPv6 address for
                                the IPv4 source address.

---> Reply with the IPv6 source
                                           address and the IPv6
                                           destination address.

Translate IPv4 to IPv6.

===> IPv6 data

Reply data to
                                                        host4

<=== IPv6 data

Translate IPv6 to IPv4

<============================== IPv6 data

3.2 Communication from an IPv6 node to an IPv4 node

In a case where communication is triggered by "host6", its query to
    resolve 'AAAA' record for "host4" is eventually delivered to one of
    extension name servers. After interaction is symmetric to the case
    described in Sention 3.1.

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INTERNET-DRAFT                                           November 1997

4. Security Consideration

Header conversions of AH [AH] and ESP [ESP] are cryptographically
    impossible. This is a big disadvantage of header conversion router
    approach. On the other hand, it is possible to use AH and ESP in
    proxy gateway approach.

5. References

[AH] Stephen Kent and Randall Atkinson, "IP Authentication Header",
        Internet-Draft, July 1997.

[ESP] Stephen Kent and Randall Atkinson, "IP Encapsulating Security
        Payload (ESP)", Internet-Draft, July 1997.

[HDRCNV] Erik Nordmark, "IPv4/IPv6 Stateless Header Translator",
        Inernet-Draft, July 1997.

[IPV4] J. Postel, "Internet Protocol", RFC 791, September 1981.

[IPV6] S. Deering and R. Hinden, "Internet Protocol, Version 6
        (IPv6) Specification", RFC 1883, January 1996.

[TRANS-MECH] R. Gilligan and E. Nordmark, "Transition Mechanisms for
        IPv6 Hosts and Routers", RFC 1933, April 1996.

10. Author's Addresses

Kazuaki TSUCHIYA
    Hitachi, Ltd.
    Hitachi Systemplaza Shinkawasaki
    890 Kashimada, Saiwai, Kawasaki, 211 Japan

Phone: +81-44-549-1714
    Fax:   +81-44-549-1721
    Email: tsuchi@isrd.hitachi.co.jp

Munechika SUMIKAWA
    Office Systems Division, Hitachi, Ltd.
    810 Shimoimaizumi, Ebina-shi 243-04 JAPAN

Phone: +81-462-35-2111
    FAX:   +81-462-35-8325
    EMail: sumikawa@ebina.hitachi.co.jp

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INTERNET-DRAFT                                           November 1997

Ken WATANABE
    Hitachi, Ltd.
    Hitachi Systemplaza Shinkawasaki
    890 Kashimada, Saiwai, Kawasaki, 211 Japan

Phone: +81-44-549-1714
    Fax:   +81-44-549-1721
    Email: nabeken@isrd.hitachi.co.jp

Yoshifumi ATARASHI
    Office Systems Division, Hitachi, Ltd.
    810 Shimoimaizumi, Ebina-shi 243-04 JAPAN

Phone: +81-462-35-2111
    FAX:   +81-462-35-8325
    EMail: atarashi@ebina.hitachi.co.jp

Takahisa MIYAMOTO
    Hitachi, Ltd.
    Hitachi Systemplaza Shinkawasaki
    890 Kashimada, Saiwai, Kawasaki, 211 Japan

Phone: +81-44-549-1714
    Fax:   +81-44-549-1721
    Email: t-miyamo@isrd.hitachi.co.jp

Kazu YAMAMOTO
    Nara Institute of Science and Technology
    8916-5 Takayama, Ikoma City 630-01 JAPAN

Phone: +81-7437-2-5322
    FAX:   +81-7437-2-5329
    EMail: Kazu@Mew.org

Jun MURAI
    Keio University
    5322 Endo, Fujisawa 252 JAPAN

Phone: +81-466-47-5111
 Fax: +81-466-49-1101
 EMail: jun@wide.ad.jp</pre>

A Communication Mechanism between IPv4 and IPv6

Expires in six month K. Watanabe, Hitachi Y. Atarashi, Hi...

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