At work today I had to disable replication to one of our 3 DCs. Unfortunately the internet wasn’t very forthcoming with such information, so after much scrabbling around and some google-fu I arrived at the following.

To disable replication you can run:

repadmin /options <your_dc> +DISABLE_INBOUD_REPL
repadmin /options <your_dc> +DISABLE_OUTBOUND_REPL

And to re-enable it again:

repadmin /options <your_dc> -DISABLE_INBOUND_REPL
repadmin /options <your_dc> -DISABLE_OUTBOUND_REPL

Finally, if you want to check the status of replication you can run

repadmin /showrepl

on the DC you want to know about.