New DC Unable to Get rID Set

I recently added another domain controller (DC) to my SBS2011 R2 network. I checked it out at the command line with >DCDiag /dnsall and found it wasn't working. Further tests with >DCDIAG /dnsall showed me that my new DC didn't receive an rID Set from the rID Master.

Running >repadmin /options <Main DC Name> showed that both inbound and outbound replications were switched off, I switched them back on and my new DC received an rID Set almost immediately.

To reset INBOUND/OUTBOUND DC replications and ensure that they are switched on run the following commands:
>repadmin /options +DISABLE_INBOUND_REPL <Main DC Name>

>repadmin /options -DISABLE_INBOUND_REPL <Main DC Name>

>repadmin /options +DISABLE_OUTBOUND_REPL <Main DC Name>

>repadmin /options -DISABLE_OUTBOUND_REPL <Main DC Name>

Useful commands for domain controller testing:
>NSLookup /?
>DCDiag /?
>repadmin /?

You can have as many DCs as you need on an SBS network as long as the FSMO rID Master role remains on the SBS server.