I have a Linksys WAG54G router. I configure it to have ports 25 and 110 open for my Exchange server, and HTP for web.
However, it randomly seems to close almost all ports, mostly putting them in Stealth mode!
This will happen frequently through the day.
I may try to collect email via POP3 and find I get an error from the server. If I then connect to my server (through the router/firwall incidentally) and run ShieldsUp, I see the ports in stealth.
All I have to do is connect to the router from teh server, save the ort Forwarding settings (no need to change them first) and ShieldsUp will tell me the ports are open again.
POP mail will then download.
Anywhere from 10 to 60 minutes later, the ports will have closed again and I have to repeat the whole farce.
I have tried upgrading and downgrading the firmware to all the versions I can find on the Linksys ftp site, to no avail.
I thought Cisco were supposed to be good but this is frustrating me. The only answer Linksys can give is "take it back and replace it".