Because my last "howto" post about an Eclipse issue ended up helping someone, I'm posting another.
I have PPTP set up on my Linux-based desktop, but I had been having no end of problems with large file transfers or long-running connections over it. They appeared to freeze up or die halfway through.
Unfortunately this was all happening when I was trying to access a remote CVS server. After I spent two hours diagnosing the poor CVS server I determined that there wasn't a bloody thing wrong with it. Turning my attentions locally, I thought I'd see if there were any troubleshooting items related to pptpclient. Turns out there are:
Connections Freeze over Linux PPTP Client
In my case, it was that MTU negotiation was busted. Adding "mtu 1400" to my peer file in /etc/ppp/peers appears to have solved all issues. Huzzah!
Hopefully my adding another descriptive, keyword-laden link to the world will help others find this more quickly.