Quick test with latest 7.3beta37 says that netmap in srcnat chain still isn’t accepted (see few posts back). As for snpt/dnpt, it’s either broken too, or I’m doing something wrong (no idea what). If I have this:
/ipv6 firewall mangle
add chain=postrouting action=snpt src-address=fd00:1234:5678:9a00::/56 src-prefix=fd00:1234:5678:9a00::/56 dst-prefix=publ:icpr:efix:b700::/56
add chain=prerouting action=dnpt dst-address=publ:icpr:efix:b700::/56 src-prefix=publ:icpr:efix:b700::/56 dst-prefix=fd00:1234:5678:9a00::/56
Then ping from fd00:1234:5678:9a01::183 to internet works, but translation seems weird, because the source gets changed to publ:icpr:efix:b701:1905::183 (I’d expect publ:icpr:efix:b701::183). Response going back to that is correctly translated to fd00:1234:5678:9a01::183. But other incoming traffic is broken, because publ:icpr:efix:b701::183 gets changed to fd00:1234:5678:9a01:e6fa::183.