[tor-talk] RFC1918 addresses on outside interface

[temp5 at tormail.org]

Running a non-exit Tor relay on Linux and have iptables set up to block
inbound and outbound RFC1918 addresses on the outside interface. Notice in
the firewall logs several seemingly random private IP addresses connection
attempts to my relay port getting dropped on the outside over the past few
months. The MAC address associated with these matches my ISP's default
gateway.

Does Tor do some type of loopback on the outside int.? Or is my ISP doing
something peculiar with NAT?