It looks like the ipfilter blocklist is broken and contains rules to block all IP traffic.
From https://silo.glasz.org/antip2p.list.gz
Disabling the ipfilter in rTorrent fixes the issue. However, it would be nice to replace this feed with a working list.
From https://silo.glasz.org/antip2p.list.gz
The Scary IPv4 Internets:0.0.0.0-255.255.255.255
The Scary IPv6 Internets:0000:0000:0000:0000:0000:0000:0000:0000-FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF
Disabling the ipfilter in rTorrent fixes the issue. However, it would be nice to replace this feed with a working list.