check the LAN connection

Hi,

I was wondering if anyone might be able to help me here. Recently, i noticed that the network connection on my computer desktop goes off and back on again in a blink of the eye (very quick). This happens very very rarely. I would say "every now and then". Unfortunately, this computer(or called mail-server) is used to host emails. This brought to my attention when i was trying to send email to someone using outlook 2003 and it immediately bounced back saying "we do not relay user1@mydns.com.au". As soon as i closed up the outlook application and open it up again, the mail went thru with no drama.

I'm still guessing here. I still haven't confirmed as to what caused this problem. But for now, i suspect the connection on the mail-server.

My question is if there is some sort of software that allows to check the LAN connection. And it'd report to you if the connection went down or rather.

Any ideas?

Thank you very much in advance

Sorry, I'm not clear about your setup?  Are you saying that the computer you work on also functions as a mail server?  What sort of setup do you have?  What size LAN?  Many hubs?  Routers?  Etc.