Windows

• Wan miniport repair tool – solve VPN and dial-up error code 720 and similar PPP/PPTP errors

L2TP

• serverfault: discussion on Windows blocked L2TP server behind NAT firewall by default
• Steven Eppler’s Blog: PPTP and L2TP Ports for Firewall

SSH tunnel

• script to background reconnect ssh tunnel

   
  #!/bin/bash
   while true; do
      echo "try to connect..."
      ssh -o ServerAliveInterval=240 -p 22 -L 2225:localhost:22 user@host -N
      echo "restarting in 5 seconds.."
      sleep 5
   done
  

• autossh – automatic reconnect ssh sessions
• ssh login without password – auto
• ssh login without password – manual create