Recently, while looking for something else in /var/log on my MacBook Pro, I happened to notice that the system log file was nearly 20MB in size -- yikes! By comparison, the log file on the Mac Pro was only 117KB. Clearly something was amiss. I opened Console, and found this in the system.log file:
...
Mar 6 19:35:47 tinisin kernel[0]: SMAC: FromHostIP: could not find IP 192.168.1.15 in lookup, so drop
Mar 6 19:35:48 tinisin kernel[0]: SMAC: FromHostIP: could not find IP 192.168.1.15 in lookup, so drop
Mar 6 19:35:49 tinisin kernel[0]: SMAC: FromHostIP: could not find IP 192.168.1.15 in lookup, so drop
.../Library/Application\ Support/VMware\ Fusion/vmnet-apps.sh stop
As soon as I ran that command, the log file entries stopped appearing. When I launched VMWare Fusion again, all seemed fine -- my virtual machine restored successfully, and I was able to surf the net via the wireless connection. Even better, after quitting Fusion, the log entries did not start up again. As best I can tell, the shell script is responsible for running a DHCP server for Fusion (but that's mostly a guess).
Mac OS X Hints
http://hints.macworld.com/article.php?story=2007030619493199