Hanging on to my Internet Connection

[etal]

I've got an iMac G3, with 192MB RAM and recently moved from OS 9 to OS X 10.2.1. That's when I began to have big problems getting my dial-up connection to function as well as it did before.

Getting connected in the first place is a cinch, but most of the time, after I've been working for 2-10 minutes, my IE 5 2.2 browser suddenly hangs—the progress bar stalls and the beachball keeps spinning until a message pops up to tell me that "the specified server cannot be located." When I look at the status bars on my Internet Connect window, the Send bar show signals trying to push through, but the Receive bar is a dead blank.

Then, if I try to send mail: "Your smtp server cannot be contacted on port 25."
Or if I try to get mail: "Your pop server on port 110 timed out."

I downloaded a shareware item called Internet Connection Keeper (it sends a signal every minute), but I still run into the same problems—and although the tag on this applet tells me "Connection Failed" (i.e. it couldn't get its signal through), my Internet Connect window and my modem icon in the menu bar both tell me I'm still connected and both are still ticking off my connection time. If I pick up my phone, there's that unmistakable internet hum.

I've set my Network TCP/IP and PPP Options exactly according to the instructions of my ISP (Galaxy, a small, local company)—Connect Automatically, TCP Header Compression, Verbose Loggin. I've found that if I "disconnect," uncheck these settings, restart my Mac, check the settings on again, and then reconnect, I can sometimes have an uninterrupted session—or this may just be a fluke.

Any help would be greatly appreciated—this is so frustrating I've been avoiding my Mac!

Thanks

et al