It appears that Bigpond has made a change to their end. They occasionally do not respond to a login request. The TCP connection remains open and no error is reported so bpalogin waits indefinitely. Ie, it appears to hang. Bigpond gives up after a while and terminates the modems session, however the TCP connection remains. The only fix is to restart bpalogin.
This patch adds a timeout while waiting for any response from Bigpond over TCP. It was written for Linux and works on that platform, but it uses what are probably Unix specific features so probably won't work on Win32.
Debian users can find a packaged version here:
http://www.stuart.id.au/russell/files/debian/sarge/bpalogin
Redhat users can find a packaged version here:
http://www.stuart.id.au/russell/files/bpalogin
diff -Nur for login timeout patch