Document ID: 113275
Updated: Sep 10, 2012
Contents
Introduction
The Network Address Translation - Port Translation (NAT-PT) is an IPv6 to IPv4 translation mechanism, which allows IPv6-only devices to communicate with IPv4-only devices and vice versa. NAT-PT is designed to be deployed to allow direct communication between IPv6-only networks and IPv4-only networks transparently that use a single V4 address.
This document explains how to implement Static NAT-PT that uses a configuration example where IPv6 network nodes communicate with IPv4 network nodes that use an IPv6 mapping of the IPv4 address configured on the NAT-PT router.
Prerequisites
Requirements
Ensure that you meet these requirements before you attempt this configuration:
-
Basic knowledge of NAT concepts and operations.
-
Basic knowledge of IPv6 Addressing Scheme
-
Basic knowledge of IPv6 Static Routing
Note: NAT-PT has been deemed deprecated by IETF because of its tight coupling with Domain Name System (DNS) and its general limitations in translation, and it has proven as technology to be too complex to maintain scalable translational services. With the deprecation of NAT-PT and the increasing IPv6 transition among users has led to the introduction of NAT64. Refer to these documents for more information on NAT64:
Components Used
The configurations in this document are based on the Cisco 3700 series router on Cisco IOS® Software Release 12.4 (15)T 13.
Conventions
Refer to Cisco Technical Tips Conventions for more information on document conventions.
Configure
In this example, three routers R1, R2 and R3 are connected through a serial interface where R1 acts as NAT-PT router, which connects to the router R2 using IPv4 address and to R3 using IPv6 address.
Note: NAT-PT is not supported in Cisco Express Forwarding (CEF) and has to be disabled.
Note: Use the Command Lookup Tool (registered customers only) in order to find more information on the commands used in this document.
Network Diagram
This example uses this network setup:
Configurations
This example uses these configuration:
| R1 Configuration |
|---|
hostname R1
ipv6 unicast-routing
!
interface Serial0/0
ip address 192.168.30.10 255.255.255.0
duplex auto
speed auto
ipv6 nat
!
interface Serial0/1
no ip address
duplex auto
speed auto
ipv6 address 2001:DB8:3002::9/64
ipv6 enable
!
ipv6 route ::/0 2001:DB8:3002::10
ipv6 nat v4v6 source 192.168.30.9 2000::960B:202
!--- Translates the ipv4 add of R2 fa0/0 to ipv6 address.
ipv6 nat v6v4 source 3001:11:0:1::1 150.11.3.1
!--- Translates the ipv6 add of loop0 of R3 to ipv4 address.
ipv6 nat prefix 2000::/96
!--- The destination prefixes that matches 2000::/96
!--- are translated by NAT-PT.
!
end
|
| R2 Configuration |
|---|
hostname R2 ! interface Serial0/0 ip address 192.168.30.9 255.255.255.0 duplex auto speed auto ! ip route 0.0.0.0 0.0.0.0 192.168.30.10 ! ! end |
| R3 Configuration |
|---|
hostname R3 ipv6 unicast-routing ! interface Loopback0 no ip address ipv6 address 3001:11:0:1::1/64 ! interface Serial0/0 no ip address duplex auto speed auto ipv6 address 2001:DB8:3002::10/64 ! ipv6 route ::/0 2001:DB8:3002::9 ! |
Verify
Use this section in order to confirm that your configuration works properly.
In router R3
Now any packet from IPv6 address of Loopback0 of R3 should be able to reach fa0/0 IPv4 address of R2 using the IPv6 address 2000::960B:202 as shown here:
| Ping |
|---|
R3#ping 2000::960b:202 sou lo 0 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 2000::960B:202, timeout is 2 seconds: Packet sent with a source address of 3001:11:0:1::1 !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 8/60/124 ms !--- This shows that the router R3 is able to reach !--- the router R2 through lo address 3001:11:0:1::1. |
In router R2
| Ping |
|---|
R2#ping 150.11.3.1 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 150.11.3.1, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 24/68/120 ms !--- The successful ping response shows that the router R2 !--- is able to reach the IPv6 network. |
In router R1
| show ipv6 nat translations |
|---|
R1#show ipv6 nat translations
Prot IPv4 source IPv6 source
IPv4 destination IPv6 destination
--- --- ---
192.168.30.9 2000::960B:202
--- 150.11.3.1 3001:11:0:1::1
--- ---
R1#show ipv6 nat translations
Prot IPv4 source IPv6 source
IPv4 destination IPv6 destination
--- --- ---
192.168.30.9 2000::960B:202
--- 150.11.3.1 3001:11:0:1::1
--- ---
!--- This command displays the active NAT-PT translations in the router.
|
| debug ipv6 nat detailed |
|---|
R1#debug ipv6 nat detailed
R1#
*Mar 1 09:12:41.877: IPv6 NAT: Found prefix 2000::/96
*Mar 1 09:12:41.881: IPv6 NAT: IPv4->IPv6:
src (192.168.30.9 -> 2000::960B:202)
dst (0.0.0.0 -> ::)
ref_count = 1, usecount = 0, flags = 513,
rt_flags = 0, more_flags = 0
*Mar 1 09:12:41.881: IPv6 NAT: IPv4->IPv6:
src (0.0.0.0 -> ::)
dst (150.11.3.1 -> 3001:11:0:1::1)
ref_count = 1, usecount = 0, flags = 257,
rt_flags = 0, more_flags = 0
*Mar 1 09:12:41.925: IPv6 NAT: IPv6->IPv4:
src (3001:11:0:1::1 -> 150.11.3.1)
dst (2000::960B:202 -> 192.168.30.9)
ref_count = 1, usecount = 0, flags = 2,
rt_flags = 0, more_flags = 0
*Mar 1 09:12:41.925: IPv6 NAT: icmp src (3001:11:0:1::1) -> (150.11.3.1),
dst (2000::960B:202) -> (192.168.30.9)
*Mar 1 09:12:41.965: IPv6 NAT: Found prefix 2000::/96
*Mar 1 09:12:41.965: IPv6 NAT: IPv4->IPv6:
src (192.168.30.9 -> 2000::960B:202)
dst (150.11.3.1 -> 3001:11:0:1::1)
ref_count = 1, usecount = 0, flags = 2,
rt_flags = 0,
!--- This command displays detailed information about NAT-PT events.
|
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Refer to Cisco Technical Tips Conventions for information on conventions used in this document.