How does my VPN server listen for connections? 1

[Schroeder]

We don't run any services from our location and hence have set our gateway router to ignore all incoming connection requests. We do use a VPN though. Is our router listening on some port for VPN connections? If a scanner hit the right port, would it receive an answer from our router?

 

[AlexIT]

Your router is set to foreward the VPN ports to the server. Yes, someone can attempt a connection to the server on those ports, but VPN is the most secure option available now and this connection will fail. I am not aware of any hackers attempting VPN connections...anyone else seen this in their logs?

Alex

 

[Schroeder]

Well, the router itself is the VPN server. I presume that even with the router acting as the VPN server, it has to leave some port open somewhere.
The vast majority (by a large margin) of the scans that hit us are for 135. Although most of the others are on well known ports, we do receive more than a few hits on some odd-ball numbers - maybe looking for specific trojons. I don't know and have been unable to determine what port my VPN server might be listening on so I can't even tell if it's being scanned.

 

[lgarner]

VPNs use pretty standare ports. What kind is it? IPSec, PPTP, or something else?

 

[Schroeder]

IPSec. Not sure I've heard of PPTP.

 

[lgarner]

IPSec uses UDP port 500 and protocols 50 & 51.

PPTP is used by Microsoft & compatible VPN's and uses TCP port 1723 and protocol 47.

So in your case, UDP port 500 is the one that's left open.

 

[Schroeder]

Thanks for your help folks. This was just something I never understood about my router and I didn't like having that hole in my knowledge.

My logs, going back a year and a half show zero scans for either ports 500 or 1723.