From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Eric Poulin" <epoulin@onepost.net>
Subject: Re: MAC Addresses in Logfile Entries
Date: Tue, 22 Apr 2003 22:13:25 -0400
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> Some of our log entries contain MAC addresses, like this:
> Apr 20 10:15:35 foo kernel: IPT IN_FIREWALL: IN=eth1 OUT=
> MAC=00:30:48:11:94:e5:00:d0:ba:45:ec:25:08:00 SRC=XXX.XX.XX.XX
> DST=XXX.XX.XX.XX LEN=40 TOS=0x00 PREC=0x00 TTL=48 ID=0 DF PROTO=TCP
> SPT=1572 DPT=1080 WINDOW=32430 RES=0x00 SYN URGP=0
> While others don't:
> Apr 14 07:55:35 foo kernel: IPT FORWARD: IN=eth0 OUT=eth1
> SRC=XXX.XX.XX.XX DST=XXX.XX.XX.XX LEN=48 TOS=0x00 PREC=0x00 TTL=127 ID=225
> DF PROTO=TCP SPT=1047 DPT=37 WINDOW=64512 RES=0x00 SYN URGP=0
>
> I see the "OUT" field in the latter contains "eth1" instead of a MAC
> address.
>
> Can someone elaborate on the difference here? Thanks.

I'm experiencing this bahavior for a while already, and from what I can see,
I will only see the MAC address in the log ONLY if the packet was destinated
for the local machine(Or was generated BY the machine), but I will never see
MACs if the packet logged was for another machine than the firewall.

If somebody can confirm...

Eric Poulin