Only LAN computers can connect VPN

I have a multi-homed server.I have openned ports 1723 and 3389 ( for
remote desktop). Only computers connected to the private NIC can
establish VPN connection. The remote computers that connect through a
router get Error 678. I would really appreciate your input on this.

The first question is "Why do you have two NICs if you are behind a
router?" If you did this just to get VPN you have wasted your time, because
it isn't necessary. The normal LAN NIC can handle it.

It isn't simply a matter of opening port 1723. It is a matter of
forwarding it from the router to the RRAS server. The client connects to the
public interface of the router. To extend that connection to the server on
the LAN, you need to forward pptp (tcp port 1723) to the server on the LAN.
The NIC you forward it to should be using the router as its default gateway
(for the return traffic to get back to the Internet gateway).

john wrote:
> I have a multi-homed server.I have openned ports 1723 and 3389 ( for
> remote desktop). Only computers connected to the private NIC can
> establish VPN connection. The remote computers that connect through a
> router get Error 678. I would really appreciate your input on this.

If the port forwarding is set up correctly but you get an error 721,
something in the path is probably blocking GRE. If your router is set up to
do this (it can be called VPN passthorough or PPTP passthrough) but it still
fails, check that you have the latest firmware upgrade for the router.

Bill Grant wrote:
> The first question is "Why do you have two NICs if you are behind a
> router?" If you did this just to get VPN you have wasted your time,
> because it isn't necessary. The normal LAN NIC can handle it.
>
> It isn't simply a matter of opening port 1723. It is a matter of
> forwarding it from the router to the RRAS server. The client connects
> to the public interface of the router. To extend that connection to
> the server on the LAN, you need to forward pptp (tcp port 1723) to
> the server on the LAN. The NIC you forward it to should be using the
> router as its default gateway (for the return traffic to get back to
> the Internet gateway).
> john wrote:
>> I have a multi-homed server.I have openned ports 1723 and 3389 ( for
>> remote desktop). Only computers connected to the private NIC can
>> establish VPN connection. The remote computers that connect through a
>> router get Error 678. I would really appreciate your input on this.