Site to Site VPN works but can't join domain on other side

  • DC on site A.
    Clients on site B can ping DC, can browse SMB shares but cant join domain. DNS requests to DC from site B time out sometimes. When site B router is set as DNS forwarder to DC, there are no DNS timeouts but still cant "contact DC" even though I can ping and resolve FQDN. Help please….

  • There are multiple ways of solving this issue assuming it's DNS related.  Some solutions are more efficient than others, but let's say your domain is

    • Leverage the DNS forwarder and add to the Domain Overrides.

    • Configure a DNS server on site B.  Add a conditional forwarder for that is pointed at the DC on Site A

    • Configure a DNS server on site B.  Add a primary forward zone for and create an "A" record for and point it at the DC on Site A

    • In theory, you could also do this -> While option 1 is in play (or add to the hosts file here), Spin up a Server on Site B, join the domain, promote this server to a backup domain controller.

    • Add to the hosts file on every machine in site B.  (A management nightmare and the most inefficient method, but will work)