General discussion


IP6 / IP4 interoperability

By BennyHell ·
hi all,

Has anybody here implemented an isolated IP6 testing environent within an existing IP4 LAN? Basically, I'm implementing an IP6 development area where I can test multiple Unix, Windows, Linux clients using single / dual stack IP4/6.

I already have an isolated scenario, which is basically an isolated Cisco switch (we're a Cisco house) , but I'd like to give my user base the ability to copy code etc.. to the IP6 area, and also provide them access to DNS AAAA records, DHCP 6 etc...

If anybody would like to make any suggestions, or quote from experience, I'm all ears.

I am toying with the idea placing a dual homed Linux box in a firewall roll between both Lans, or using an old Cisco 1700 router to manage the routing, although I have not arrived at any IP4-IP6 address translating strategy as of yet.



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To put it!

by Why Me Worry? In reply to IP6 / IP4 interoperabilit ...

IPv4 is a challenge in itself without having to deal with 64 bit addresses in IPv6.

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by BennyHell In reply to To put it!

superb; thanks.

Multistack on the backbone it is.


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Hardware Infrastructure

by JCAlexandres In reply to IP6 / IP4 interoperabilit ...

Take a look to the hardware infrastructure requirements to support IP6, I don't know how advanced you are in your study, but this information seems to be the angular stone.

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by Zontago In reply to Hardware Infrastructure

Hi, I do think that I understand IPV4. The rules should generaly stay the same excluding the classes. But I'd bet that you will need two interfaces on a device - i.e. a router of a PC - for routing between IPV4 & IPV6.

Keep us posted!

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Working scenario since July

by BennyHell In reply to IP6 / IP4 interoperabilit ...

I got this working using a Cisco 2600, IOS 12.3(22)

Basically, I have one NIC of the 3600 on the IP4 side, one on the IP6 side, which connects into a dedicated Cisco switch, which all the IP6 servers also pacth into.

I successfully configured NAT-PT, using v4v6 and v6v4 static NATs, along with dynamic NAT for IP4 to IP6.


ipv6 unicast-routing
interface FastEthernet0/0
ip address
duplex auto
speed auto
ipv6 nat

interface FastEthernet0/1
no ip address
duplex auto
speed auto
ipv6 address 2001:CC1E:1::64/64
ipv6 enable
ipv6 nat
ipv6 nat translation udp-timeout 600
ipv6 nat v4v6 source 2001:CC1E:1::A02:231
ipv6 nat v4v6 source 2001:CC1E:1:203:BAFF:FE6F:3E91
ipv6 nat v4v6 source 2001:CC1E:1:203:BAFF:FE66:240B
ipv6 nat v6v4 source list ip6list pool v4pool
ipv6 nat v6v4 source 2001:CC1E:1::A02:231
ipv6 nat v6v4 source 2001:CC1E:1:203:BAFF:FE66:240B
ipv6 nat v6v4 source 2001:CC1E:1:203:BAFF:FE6F:3E91
ipv6 nat v6v4 pool v4pool prefix-length 24
ipv6 nat prefix 2001:CC1E:1:96
ipv6 access-list ip6list
permit ipv6 2001:CC1E:1:64 any


Obviously the IP addresses of some of the IP6 servers are:

Useful Cisco commands:
sh ipv6 nat translations
sh ipv6 nat statistics

Best regards,


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