We have a Dell PE1850 running Netware 6.5Sp7, and Edir 8.8SP5, the latest tcpic, wsock patches, scsihd for Sp7 etc have all been applied. It is our eDirectory master, reference time server, and an SLP DA.

Once every couple of weeks or so the server will become completely unresponsive from the network.
Looking at the console everything appears fine, no logged messages saying it has lost connection to the network or other servers.
If you load any module at all (monitor, ping, dsrepair have been tried), the system console just becomes totally unresponsive. Already loaded modules work as normal.

I have already updated the ians driver (the NIC's are in a failover team, e1000 was at the latest version available) to the latest version, but the issue reoccured last night.

I've taken to leaving monitor running and not found anything to be an obvious culprit, CPU is at a couple of percent usage. Today though it was stuck around 40% with 'FLAIM System Monitor' and 'OS Allocated Bus Interrupt' being the heavy hitters under busiest threads -

Also when it crashes I've been dropping to debug via shift+shift+alt+escape, a ? has been returning lsl.nlm.

My next planned step is to break the failover team and run off a single NIC, after that I'd be looking at SP8.

Does anyone have any further advice or suggestions on how to diagnose this issue?

Thanks in advance,