Conditional routing over PPTP help required

Scope · 10 Jan 2015 at 15:57

Im trying to configure my PPTP client (ubuntu) to only send traffic to IP x.x.x.x over PPTP, the rest directly out from my internet connection - but it is either all or nothing.. Any idea how I can configure PPTP to work in that manner?

Caged · 10 Jan 2015 at 16:14

Don't add your PPTP VPN as the default gateway, then add a static route to send traffic for your specific IP over that interface.

Scope · 10 Jan 2015 at 16:22

@Caged, OK I think I know what you mean.. By PPTP as default gateway do you mean dont add this command:

sudo route add -net "0.0.0.0/0" dev "ppp0"

? This as far as I can see would send all traffic to PPTP.. I have tried adding a specific IP to the route add command, but it returns an error, so I am obviously doing something wrong:

sudo route add -net "x.x.x.x" dev "ppp0"
SIOCADDRT: Invalid argument

It would be useful if somebody could tell me the command to run to pass all traffic from x.x.x.x to "ppp0".

PS: I followed this tutorial for installing PPTP, which works fine, but doesnt go into details for adding conditional routing.

Caged · 10 Jan 2015 at 16:31

I think you want route add -host instead of -net if it's just a single IP.

Scope · 10 Jan 2015 at 17:10

Yes -host updates the routing table, but it still doesnt appear to work.. I will try to route something easier to debug first of all, then see..

Thank for your help @Caged.

Caged · 11 Jan 2015 at 00:07

I think you might still need to give it a gateway, in your case this will be whatever your gateway address was changed to when you established the VPN and it wasn't a split-tunnel configuration.