Hope this is in the right place.

I have a vpn setup between the above two routers and apart from the following problem all is well.

Problem.

I have a domain setup with a domain controller on the 192.168.1.xxx side.
I have a small branch office setup on the 192.168.4.xx side.

I would like to be able to setup the routers so that the clients on the 192.168.4.xx side can logon to the domain.

At the moment it looks like they are but in there error logs i am getting event id 1054 A domain controller cannot be found. They can see the domain controller and access the resources and ping it but cant find it at logon so i would like to know if i have to set up some sort of port forwarding for them to be able to logon properly to the domain controller.

Any help is much appreciated

Gareth