I had a problem where for no good reason I could see, my smoothwall firewall would keep disconnecting me from the Internet. If I rebooted the pc it would start to work fine for a while, but would eventually do it again.
I trawled though the logs (no mean feat considering i’m a windows user, and hardly know Linux at all!), and managed to sus out it was something wrong hardware wise with my usb modem, or my isp was having problems.
When I left my PC plugged straight into the modem, I had no problems. So I was going to try and replace the usb card in the pc. Before I did that I thought it might possibly be a power issue (the pc that runs the firewall is quite old and only has an atx mini power supply), so I bought a cheap powered usb hub to run the modem of to see if that helped.
Well, it did! I’ve ran the firewall up for nearly 2 days now and not one disconnect. This might mean my firewall hardware is on its way out, but at least I solved my problem short term!
More info on smoothwall can be found at www.smoothwall.org