Difference between revisions of "IPv4-Mapped IPv6 Address"
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IPv4-mapped IPv6 addresses are used in scenarios where IPv6 an IPv6-only application need to communicate with an IPv4 only application using IPv4 packets. | IPv4-mapped IPv6 addresses are used in scenarios where IPv6 an IPv6-only application need to communicate with an IPv4 only application using IPv4 packets. | ||
| + | =IPv4-mapped address= | ||
| + | |||
| + | The IPv4-mapped address, 0:0:0:0:0:FFFF:w.x.y.z or ::FFFF:w.x.y.z, is used to represent an IPv4-only node to an IPv6 node. It is used only for internal representation. The IPv4-mapped address is never used as a source or destination address for an IPv6 packet. The IPv6 protocol does not support the use of IPv4-mapped addresses.<ref>http://technet.microsoft.com/en-us/library/cc759208(WS.10).aspx</ref> | ||
| + | |||
| + | =IP Addresses with a Dual-Stack Socket= | ||
| + | Dual-stack sockets always require IPv6 addresses. The ability to interact with an IPv4 address requires the use of the IPv4-mapped IPv6 address format. Any IPv4 addresses must be represented in the IPv4-mapped IPv6 address format which enables an IPv6 only application to communicate with an IPv4 node. The IPv4-mapped IPv6 address format allows the IPv4 address of an IPv4 node to be represented as an IPv6 address. The IPv4 address is encoded into the low-order 32 bits of the IPv6 address, and the high-order 96 bits hold the fixed prefix 0:0:0:0:0:FFFF. The IPv4-mapped IPv6 address format is specified in RFC 4291. For more information, see www.ietf.org/rfc/rfc4291.txt. The IN6ADDR_SETV4MAPPED macro in Mstcpip.h can be used to convert an IPv4 address to the required IPv4-mapped IPv6 address format. | ||
| + | |||
| + | If the underlying protocol is actually IPv4, then the IPv4 address is mapped into an IPv4-mapped IPv6 address format. That is the, family field in the SOCKADDR structure indicates AF_INET6, but an IPv4-mapped IPv6 address is encoded in the IPv6 address structure. For a dual-stack socket in listening mode, this means that any accepted IPv4 connections will return an IPv4-mapped IPv6 address. For a dual-stack socket that is connecting to an IPv4 destination, the SOCKADDR structure passed to connect must be an IPv4-mapped IPv6 address. Applications must take care to handle these IPv4-mapped IPv6 addresses appropriately and only use them with dual stack sockets. If an IP address is to be passed to a regular IPv4 socket, the address must be a regular IPv4 address not a IPv4-mapped IPv6 address.<ref>http://msdn.microsoft.com/en-us/library/windows/desktop/bb513665(v=vs.85).aspx</ref> | ||
| + | |||
| + | =Examples= | ||
| + | Only seen working application using IPv4-mapped IPv6 addresses is Windows 7 ping!!! | ||
| + | <source lang=cli> | ||
| + | <input> | ||
| + | C:\Users\Henrik thomsen><notice>ping ::ffff:192.168.139.50</notice> | ||
| + | |||
| + | Pinging 192.168.139.50 with 32 bytes of data: | ||
| + | Reply from 192.168.139.50: bytes=32 time<1ms TTL=62 | ||
| + | Reply from 192.168.139.50: bytes=32 time<1ms TTL=62 | ||
| + | Reply from 192.168.139.50: bytes=32 time<1ms TTL=62 | ||
| + | Reply from 192.168.139.50: bytes=32 time<1ms TTL=62 | ||
| + | |||
| + | Ping statistics for 192.168.139.50: | ||
| + | Packets: Sent = 4, Received = 4, Lost = 0 (0% loss), | ||
| + | Approximate round trip times in milli-seconds: | ||
| + | Minimum = 0ms, Maximum = 0ms, Average = 0ms | ||
| + | |||
| + | </input> | ||
| + | </source> | ||
| + | or same as | ||
<source lang=cli> | <source lang=cli> | ||
<input> | <input> | ||
| − | C:\Users\Henrik thomsen><notice>ping ::ffff: | + | C:\Users\Henrik thomsen><notice>ping ::ffff:c0a8:8b32</notice> |
| − | Pinging 192.168. | + | Pinging 192.168.139.50 with 32 bytes of data: |
| − | Reply from 192.168. | + | Reply from 192.168.139.50: bytes=32 time<1ms TTL=62 |
| − | Reply from 192.168. | + | Reply from 192.168.139.50: bytes=32 time<1ms TTL=62 |
| − | Reply from 192.168. | + | Reply from 192.168.139.50: bytes=32 time<1ms TTL=62 |
| − | Reply from 192.168. | + | Reply from 192.168.139.50: bytes=32 time<1ms TTL=62 |
| − | Ping statistics for 192.168. | + | Ping statistics for 192.168.139.50: |
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss), | Packets: Sent = 4, Received = 4, Lost = 0 (0% loss), | ||
Approximate round trip times in milli-seconds: | Approximate round trip times in milli-seconds: | ||
| − | Minimum = | + | Minimum = 0ms, Maximum = 0ms, Average = 0ms |
</input> | </input> | ||
</source> | </source> | ||
| + | =References= | ||
| + | <references/> | ||
{{source cli}} | {{source cli}} | ||
Latest revision as of 08:29, 25 November 2011
| IPv6 Address Type: | IPv4 Mapped |
| Prefix: | ::ffff/96 |
| Local Routeable: | Yes |
| Global Routeable: | Yes |
| Global Unique: | Yes |
| Example: | ::ffff:83.90.47.30 |
| IPv4 Equivalent: | None |
| Described in: | rfc4291 |
| rfc4038 section 4.2 | |
These addresses are used to embed IPv4 addresses in an IPv6 address. One use for this is in a dual stack transition scenario where IPv4 addresses can be mapped into an IPv6 address.
See RFC 4038 for more details
IPv4-mapped IPv6 addresses are used in scenarios where IPv6 an IPv6-only application need to communicate with an IPv4 only application using IPv4 packets.
IPv4-mapped address
The IPv4-mapped address, 0:0:0:0:0:FFFF:w.x.y.z or ::FFFF:w.x.y.z, is used to represent an IPv4-only node to an IPv6 node. It is used only for internal representation. The IPv4-mapped address is never used as a source or destination address for an IPv6 packet. The IPv6 protocol does not support the use of IPv4-mapped addresses.[1]
IP Addresses with a Dual-Stack Socket
Dual-stack sockets always require IPv6 addresses. The ability to interact with an IPv4 address requires the use of the IPv4-mapped IPv6 address format. Any IPv4 addresses must be represented in the IPv4-mapped IPv6 address format which enables an IPv6 only application to communicate with an IPv4 node. The IPv4-mapped IPv6 address format allows the IPv4 address of an IPv4 node to be represented as an IPv6 address. The IPv4 address is encoded into the low-order 32 bits of the IPv6 address, and the high-order 96 bits hold the fixed prefix 0:0:0:0:0:FFFF. The IPv4-mapped IPv6 address format is specified in RFC 4291. For more information, see www.ietf.org/rfc/rfc4291.txt. The IN6ADDR_SETV4MAPPED macro in Mstcpip.h can be used to convert an IPv4 address to the required IPv4-mapped IPv6 address format.
If the underlying protocol is actually IPv4, then the IPv4 address is mapped into an IPv4-mapped IPv6 address format. That is the, family field in the SOCKADDR structure indicates AF_INET6, but an IPv4-mapped IPv6 address is encoded in the IPv6 address structure. For a dual-stack socket in listening mode, this means that any accepted IPv4 connections will return an IPv4-mapped IPv6 address. For a dual-stack socket that is connecting to an IPv4 destination, the SOCKADDR structure passed to connect must be an IPv4-mapped IPv6 address. Applications must take care to handle these IPv4-mapped IPv6 addresses appropriately and only use them with dual stack sockets. If an IP address is to be passed to a regular IPv4 socket, the address must be a regular IPv4 address not a IPv4-mapped IPv6 address.[2]
Examples
Only seen working application using IPv4-mapped IPv6 addresses is Windows 7 ping!!!
<input>
C:\Users\Henrik thomsen><notice>ping ::ffff:192.168.139.50</notice>
Pinging 192.168.139.50 with 32 bytes of data:
Reply from 192.168.139.50: bytes=32 time<1ms TTL=62
Reply from 192.168.139.50: bytes=32 time<1ms TTL=62
Reply from 192.168.139.50: bytes=32 time<1ms TTL=62
Reply from 192.168.139.50: bytes=32 time<1ms TTL=62
Ping statistics for 192.168.139.50:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 0ms, Maximum = 0ms, Average = 0ms
</input>or same as
<input>
C:\Users\Henrik thomsen><notice>ping ::ffff:c0a8:8b32</notice>
Pinging 192.168.139.50 with 32 bytes of data:
Reply from 192.168.139.50: bytes=32 time<1ms TTL=62
Reply from 192.168.139.50: bytes=32 time<1ms TTL=62
Reply from 192.168.139.50: bytes=32 time<1ms TTL=62
Reply from 192.168.139.50: bytes=32 time<1ms TTL=62
Ping statistics for 192.168.139.50:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 0ms, Maximum = 0ms, Average = 0ms
</input>