NAT-PT only works up to 50%

[Kyle Lenderlof]

I want to test NAT-PT (I know it's deprecated) between an IPv4 host (Host_B) and an IPv6 host (Host_A).

Host_A<---->881<---->Host_B

Host_A and Host_B are directly connected to the Router.

Host_A: 2001:345::2/64

Host_B: 192.168.123.2

　

ipv6 uni

!

int vlan2

ipv6 address 2001:345::1/64

ipv6 nat

!

int fa2

switchport mode access

switchport acc vlan 2

!

int vlan3

ip address 192.168.123.1 255.255.255.0

ipv6 nat

!

int fa3

switchport mode access

switchport acc vlan 3

!

ipv6 nat prefix 2001:12::/96

ipv6 nat v4v6 source 192.168.123.2 2001:12::c0a8:7b02

ipv6 nat v6v4 source 2001:345::2 192.168.45.2

ping 192.168.45.2 on Host_B to Host_A works

but ping 2001:12::c0a8:7b02 on Host_A to Host_B doesn't work, why?

Router(config)#do sh ip int brief
Any interface listed with OK? value "NO" does not have a valid configuration

Interface                  IP-Address      OK? Method Status                Protocol
FastEthernet0              unassigned      YES unset  down                  down
FastEthernet1              unassigned      YES unset  down                  down
FastEthernet2              unassigned      YES unset  up                    up
FastEthernet3              unassigned      YES unset  up                    up
FastEthernet4              unassigned      YES NVRAM  administratively down down
NVI0                       unassigned      NO  unset  up                    up
Vlan1                      unassigned      YES unset  down                  down
Vlan2                      unassigned      YES unset  up                    up
Vlan3                      192.168.123.1   YES manual up                    up

Thanks for your answer!!

[Kyle Lenderlof]

I got more information with debug ipv6 nat detail

IPv6 NAT: Dropping v6tov4 packet

IPv6 NAT: IPv6->IPv4:

                 src (:: -> 0.0.0.0)

                 dst (2001:12::C0A8:7B02 -> 192.168.123.2)

                 ref_count = 1, usecount = 0, flags = 513,

                 rt_flags = 0, more_flags = 0

Why is there no source address on the IPv6 only host? So the ping fails.

The destination address is correct.

[abdel_n]

Hi 123Kyle123,

Before proceeding with any NAT-PT, make sure you have successful IPv6 ping between your router and Host_A as well as successful IPv4 communication between the router and Host_B.

I suspect a problem with ND, in the IPv6 segment.

Enable ND debug and try to ping Host_A and let's see what will happen.

,

[abdel_n]

Just in case here is a video with detailed deployment of static NAT-PT.

I hope it helps.

[Kyle Lenderlof]

Thanks for the video.

I solved the problem:

The Router used the IPv6-Address with Privacy Extensions for NAT-PT not my given IPv6-Address.