VPN server behind a router - can't connect?

[PetrolheaD]

Hello!

I have Cisco 871 acting as a VPN server behind another router in the same LAN. The problem is that I can't connect to the VPN from outside network using the public IP but I CAN connect to the VPN from inside the LAN using the internal IP. I've assigned a virtual server on the main router to forward the traffic (port 1723 and 47) to the VPN router but still doesn't work.

What to do?

Thanks!

[lgijssel]

This problem is actually related to  VPN over NAT. 

You also need UDP port 500, and either IP protocol 50 or 51, depending on whether you are using AH, ESP or both.

The best option is to configure IPsec over UDP instead of native. This makes the whole session NAT compatible.

regards,

Leo

[PetrolheaD]

Thanks for your answer but I forgot to mention that it's PPTP (this guide), not IPsec. So is the problem still the same?

EDIT: After hours of trying I found out that by making the default route from the VPN router to the IP of the main router got it to work.

SOLVED

THE RESOLUTION