Enable the connection [HELP] - Problems connecting to VPN with Comodo Firewall.
See also this thread. (This one is better).
I'm too lazy to add the settings to allow connection to VPN. It's easier to disable firewall during authentication and bring it back on right after.
Well, after a dozen hangups on authentication, I think I'll implement one of these solutions.
The one I implemented is listed here. It works well, allowing the VPN to connect. I used my hostname as the source address.