Which ports to forward for a VPN server that sits behind a firewall?

Question

Question pretty much says it all.

From what I have found, it seems that port 1723 is the main port to forward, but I also see numerous references to others ports.

The server that is hosting the VPN is a Windows 2008 Server.

Solution

What protocol is the VPN server using, PPTP, L2TP, IPSEC?

• PPTP uses TCP port 1723 and protocol 47
• L2TP uses UDP port 1701
• IPSEC uses UDP port 500 and protocols 50 and 51

Comments

[Axel]

Also OpenVPN uses 1194 by default. And remember that not all operate over TCP - UDP is more common.

[Dscoduc]

To clarify a bit... IPSec uses UDP 500 (and possibly UDP 4500 if behind a NAT) along with Protocol 50 and 51 instead of ports.

[Kcmamu]

Important missing detail is the fact the PPTP uses 1723/TCP, and L2TP uses 1701/UDP. Not sure where you got port 47 from! Sure you aren't thinking of Protocol 47?

[joeqwerty]

I meant to say protocol instead of port. My bad. Sorry.

[alaster]

maybe edit you post then?

[joeqwerty]

If I would have caught it I would have. since someone else caught it I didn't see any point in editing my post since they corrected me. Did you get confused by it? Sorry.

[kralyk]

Don't forget SSL VPN's, TCP port 443. The question itself should be reworded as "Which ports to forward for a (insert type here) VPN server that sits behind a firewall?" once the OP explains