Server crashing - help me find why

Question

My Mac OX 10.5.6 server has been crashing recently. I find that it has crashed, have to hardware reboot, and can't find any reason that it would have crashed. I've stayed up to date with software updates, but can't say that this started with a given update or any configuration changes that I made. There have been no recent changes in how I use the system.
Several weeks ago it started crashing with these symptoms. Server would become unresponsive to network clients and pings. I could connect the display and keyboard and see my logged in session. Could move windows. Could not open new applications.
Yesterday and last night it crashed in a new way. I discovered the fans running very fast. Server unresponsive to the network. Server unresponsive to display and to keyboard.
Survey of log files did not show anything interesting logged before the reboot. Also, I didn't notice anything interesting in the boot sequence. But there is a lot of information written there and I may not recognize interesting. The one item of interest came from daily.out and seems to indicate network interface errors on en1, the connected interface.
network:
Name Mtu Network Address Ipkts Ierrs Opkts Oerrs Coll
lo0 16384 <Link#1> 7897368 0 7897361 0 0
lo0 16384 localhost fe80::1 7897368 - 7897361 - -
lo0 16384 127 localhost 7897368 - 7897361 - -
lo0 16384 localhost ::1 7897368 - 7897361 - -
gif0* 1280 <Link#2> 0 0 0 0 0
stf0* 1280 <Link#3> 0 0 0 0 0
en0 1500 <Link#4> 00:14:51:65:99:bc 0 0 0 0 0
en1 1500 <Link#5> 00:14:51:65:99:bd 19571763 4210125 26910901 0 0
en1 1500 raindrop.lo fe80::214:51ff:fe 19571763 - 26910901 - -
en1 1500 192.168.111 raindrop.tumtum 19571763 - 26910901 - -
fw0* 4078 <Link#6> 00:11:24:ff:fe:d6:a4:6e 0 0 0 0 0
Server is configured as advanced server and running AFP, DHCP, DNS, Mail, SMB, VPN, and WEB. I usually keep myself logged in with the Server Administrator running.
I ran Disk Utility repair permissions (a few items, nothing extensive) and Verify Disk (no problems found).
I've written scripts to log output from 'netstat -i' and list of top processes every minute. If there is another crash I hope to have more information.
Sound familiar? Ideas on what to look for?
Thanks.

Answer 1

Thanks for the tip. I don't see any records like that in system.log. I've not had a crash in the past day. Running a bit torrent client with active transfers seems to trigger the crashes. I used to do this with no problem. I've switched bittorrent programs and still have the problem so it is not the bittorrent application itself. I'll run a little longer with out bittorrent, then turn it on, then try applying the patch.