I just happened to notice that when I run tcpdump on my -current system (as
of about 4 days ago) with a DLink 10/100 ethernet ("vr" driver), it begins
sending out icmp-redirects for packets that were never sent to it in the
first place (ie, a packet is sent from ether host A to ether host B, but
the -current machine at ether host C sends a redirect to A saying "hey,
send that packet to B!"). I've verified with tcpdump running on another
machine that no packets at all have the dest MAC address set to the
ethernet on this machine, and that it stops sending the icmp redirects as
soon as I exit from tcpdump (ie as soon as the ethernet is taken out of
permiscuous mode). During the time this is happening, it is also
retransmitting all the packets that *it thinks* were incorrectly sent to it.

This doesn't appear to happen with the ne driver (although I'm unable to
test exactly the same circumstances, since my ne card is 10mbit, while most
of the rest of my network is 100mbit) using the same OS, nor with the old
DE driver running on 1.3.3.

Can other people see if the same thing happens with other cards. Should I
file a PR now, or wait to see how broad ranging the problem is?