Question : Internet connection drops after period of inactivity

I have a broadband internet connection via cable modem and ethernet card.  I'm running WinXP SP1 with Norton's Personal Firewall.  When I check my computer in the morning or after a few hours my internet connection has dropped.  Typing "ipconfig /renew" on the DOS command line will not restore the connection.  Recycling the modem also does not restore the connection.  I must reboot the system in order to restore the connection.  What could be the problem?

This disconnect occurs even if I leave Outlook Express running and checking for email every 15 minutes. I suspect that this may have something to do with the firewall software.  

Answer : Internet connection drops after period of inactivity

It appears that I have found the answer to my problem and it has nothing to do with the firewall.  WinXP has a checkbox in the screen saver properties that forces a user to have to log onto the Welcome Screen whenever the screen saver activates.  Apparently, all that was neccessary was to uncheck that box in order to maintain my broadband connection.  With the box checked I lost my internet connection with or without the firewall enabled.  With the box unchecked the connection was maintained with or without the firewall.

I'm not sure why it works that way, but wouldn't you know it would turn out to be something so simple.

Thanks for the responses.