what the heck does this log entry mean?

From:	Jason King <jking at informs dot com>
To:	m0n0wall at lists dot m0n0 dot ch
Subject:	what the heck does this log entry mean?
Date:	Wed, 26 Oct 2005 15:48:59 -0500

I'm getting this log entry all over my logs in my m0n0wall:

/kernel: arp: 192.168.1.200 is on sis0 but got reply from
00:11:43:d3:5c:2a on sis2

I have no idea what it means and it's all over the place...there are
different IP's, different macs, and different interfaces listed...but
it's all over the place. Any clues?

Jason