Losing network connections

[N0ktar]

Exchnage 5.5 SP4 on WinNT 4.0
It started happening sometime yesterday for no apparent reason. Most of the users throughout the day started receiving "network problems" error when connected to Exchange with Outlook 2K. Not sure what the problem is, everything seems to work fine, the services are running, store.exe and outside connections not exessive. Any clue what's happening?

 

[chester27]

Any event messages.

 

[N0ktar]

Error: Network problems are preventing communications .....
nothing conclusive in event log.

 

[N0ktar]

I've found the solution. Alias command on pix firewall caused the issue and local traffic was being routed outside the network and blocked by access-list. TAC will have some explaining to do .