NAT64 return traffic vanishes after successful de-alias

[Eugene Grosbein]

15.12.2019 2:54, John W. O'Brien пишет:
> Hello FreeBSD Networking,
> 
> As the subject summarizes, I have a mostly-working NAT64 rig, but return
> traffic is disappearing, and I haven't been able to figure out why. I
> observe the post-translation (4-to-6) packets via ipfwlog0, but a simple
> ipfw counter rule ipfw matches nothing.

Have you read NETWORK ADDRESS TRANSLATION (NAT) section of ipfw(8) manual page carefully?
It tells:

> To let the packet continue after being (de)aliased, set the sysctl
> variable net.inet.ip.fw.one_pass to 0.

Did you set sysctl net.inet.ip.fw.one_pass=0 ?