On a 1.6.2_RC3 system my message log is getting the following:
'00:01:03:7c:a1:40 on rtk0 tried to overwrite arp info for 192.168.0.1 on
lo0'  a couple of times a day.  The rtk0 interface is connected to my DSL
modem and has a static IP address assigned by my ISP.   As this box serves
as a firewall/router for my home network I have another NIC (ex0) which has
the 192.168.0.1 address.  I'm not a sys admin (nor do I play one on TV) so
I'm not quite sure what this means.  Any thoughts...??

Thanks,

Steve