Networking – Set up VPN server on a DD-WRT router behind NAT

dd-wrtnat;networkingpptpvpn

I am trying to setup a PPTP VPN Server on my DD-WRT router behind NAT (the ISP router of my provider). I've done a lot of googling, but it seems like not many people mention about this exact scenario below:

INTERNET <–> ISP router <–> DD WRT

ISP router: WAN IP: xx.xxx.xx.xx subnet: 192.168.1.xxx router ip: 192.168.1.1

DD WRT (My Router): WAN IP: 192.168.1.10 subnet: 10.170.1.xxx router ip: 10.170.1.1

VPN server enabled with PPTP chap secret: thomas * password *

The ISP router is something I cannot touch. I do not have the login to the router, and the ISP is not going to change any settings (eg. DMZ) for me.

I've tried to sign up for a VPN service (StrongVPN), and have my DD-WRT router connect to that VPN so it can get a public WAN ip address (let's say 123.123.123.123). I succeeded in getting the WAN IP address, but when I use another computer (from an external network), and connect to 123.123.123.123, for some reason StrongVPN immediately cuts the connection.

I'm pretty frustrated at the moment, and hope some network experts out there can shed me some light.

Your help is appreciated!

Best Answer

A PPTP server requires TCP Port 1723, as well as IP Protocol 47 (GRE) to be forwarded to it. Assuming your ISP router handles port forwarding, you won't be able to run a PPTP server through this without having the ports forwarded to it.

I don't believe there are any actual VPN server solutions that will work without the relevant ports being forwarded to it.

There may be other software solutions that mimic a similar interface, but I have no recommendations for this and software recommendations are outside of the remit of this site. Your best bet would be to search for something along the lines of VPN server without port forwarding.

There is a similar topic here although this isn't specific to VPN, depending on your requirements it may still be helpful.

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