We have two separate buildings, with a DC in each and a radio link between them. The link went down last week, one building is fine but Active Directory in the second building won't start. After doing a bit of research I think I should have set these up as two separate sites. Any recommendations on what I do now? Can I "force" some roles on to the second server so that active directory will start in that building?

I don't want to do something that will stop them syncing when the link is repaired. After the link is repaired will putting them in separate sites assign them the required roles so that if we lose connection they will both continue to work?

Here is an output from NTSDUTIL on the second server (LST) that won't start. LS2 is the server in the other building that is running fine.

I also want to set up a VPN connection between the two so we have a backup system. Is there any issue doing this on machines with only one network port?