Originally Posted by Lord Estraven
I'm using a non-IPV6 mirror, and NetBSD tries IPV6 anyway.
That's...strange. Have you tried switching to a different non-ipv6 mirror? It's always possible it's listed as non-ipv6 when in reality it is ipv6. You can run "ftp -4 <your mirror url>" to force it to use an ipv4 address for that url, but I don't know how effective that would be over time.
As for sysctl.conf, you can likely run "sysctl net.inet6" to see what your options are for monkeying around with sysctl options. If you find one you want to tweak, you can assign to it like such: "sysctl net.inet6.ip6.forwarding=1" (0 to turn off, 1 to turn on, usually).