after fighting with this tedious 10053 error for 2 months, we have a working solution at least for Win2k Professional using a common cable/broadband modem (rcn).
We added several tcp/ip parameters to the registry that normally are not present on OEM & retail Win2k versions, but are common on the enterprise server OS, SB Server & the venerable NT3.5 & 4.0 systems.
Since this error is obviously caused by a SYN/ACK parameter change in winsock, which we believe is a result of one if not several hastily issued critical updates from Microsoft, the easiest way to correct it would be to modify the now-inadequate tcp/ip packet parameters.
All of the TCP/IP parameters are registry values that are located under one of two different subkeys of
Adapter Name\Parameters\Tcpip
A total of 9 new parameters i added, and upon reboot, my 10053 error that occured every 10 minutes was history. I've been connected to efnet for 28 straight hours since, with no errors. The entire registry mod takes less than 10 minutes.
email me for the full document on this registry fix.

i can resist everything except temptation....