IPv6 NAT-PT - ARP issue

Hello,
 I have a simple setup where one router in the middle does IPv6 NAT-PT
translation. Everything looks good where IPv6 is translated to IPV4 (both
the source and destination), the ping gets to the destination (verified with
debug ip icmp) but on the way back the response gets lost.

With this setup (R6 has configured NAT-PT):
SW1 (FC00:1:0:67::7) ------------------ > R6 -------------------> R4
(150.1.4.4)

R6 NATing
src (FC00:1:0:67::7) -> (155.1.146.*7*),
dst (2000::9601:404) -> (150.1.4.4)

the problem is that when R4 ARPs for 155.1.146.*7* it comes up INCOMPLETE.

Rack1R4#sh arp | i 155.1.146
Internet 155.1.146.1 219 001e.f725.0b60 ARPA
GigabitEthernet0/1
Internet 155.1.146.4 - 001e.f766.c621 ARPA
GigabitEthernet0/1
Internet 155.1.146.6 49 001e.f702.a7a0 ARPA
GigabitEthernet0/1
Internet 155.1.146.*7 * 0 Incomplete ARPA

For reference this is the nat config on R6:

interface GigabitEthernet0/0.67
 ipv6 nat
interface GigabitEthernet0/0.146
 ipv6 nat
ipv6 nat v4v6 source 150.1.4.4 2000::9601:404
ipv6 nat v6v4 source FC00:1:0:67::7 155.1.146.7
ipv6 nat prefix 2000::/96

Anyone have any ideas what could be wrong?

Thank you,

Tom

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Received on Tue Jul 13 2010 - 22:28:40 ART