I have a new BM 3.8 SP2A server with TCP657HA and BM38FP3C applied (the latter two only today). Every 40mins or so I get a micro-outage on my external interface - it lasts for about 5-15 seconds. External parties can't ping/email me and I can't ping/connect out. It doesn't seem to happen at night when there aren't any users putting load on the server. We're talking about secondary IP addresses with static NAT. I'm not sure whether it's filtering, NAT, or OS-level TCP so I posted here.

Any ideas on what could be wrong?

Other details:
Server - HP ML350 G4 with 4 procs and 2Gb RAM
2 x 5Gb trad cache volumes
Internal NIC: Q57 driver
External NIC: NC7170 with N1000.LAN 7.24 dated 4 August 2003