For example, McAfee will do it IF the settings on a particular machine are set to scan "network drives" and that specific machine has mapped network drives, it may be doing a scheduled full system scan which includes a check all network connections..
Or if the scan is completely random, then maybe an antivirus/antispyware scanner has similar settings and someone is running it manually with the "network scanning" option enabled.. Obviously, that's an incorrect setting for most computers but it is possible.
One other possibility comes to mind as we've had something similar here in the past.. Quite a few virus/worms are network aware and have the ability to scan the network checking for shared drives (NETBIOS) in the network machines.. We had one years ago (W32/QAZ.worm)which had the ability to breach routers in our WAN.. It doesn't happen any more, but it did.
Hope this helps.
I'm boggled... Every so often a computer on a network I manage will do a network scan on ports 139, 445 and 2048. It is not consistent in regards to time of day, etc. What, on a normal Windows XP OS SP2 with MS Office, could cause this to occur? I can't seem to link the network scans to a particular event or application. Please help!
Thanks in advance.