TCP over TCP

Why is it that VPNs are so unstable? I’ve used different VPN software over the years, and have had problems with all of them. I’m always fighting to keep my VPN tunnel up and running. The PPTP (*snicker*) based VPNs I’m using gives me a lot of grief.

Now I finally understand why my VPN (and tunnels in general) are so unstable. TCP’s retransmission algorithm wasn’t designed to work in a tunnel. This link explains it far better than I can: Why TCP Over TCP Is A Bad Idea