Repadmin gives operational error 58

While testing some remote DC's, "repadmin /replsummary" ended with an error of

   Experienced the following operational errors trying to retrieve replication information:
       58 - mydc1.mydomain.com
       58 - mydc2.mydomain.com

Information for "Source DSA" for mydc1 and mydc2 both show up with 0 fails/errors; the information is lacking under Destination DSA. This domain controller I ran the command on (remotedc1) can see mydc1 and mydc2.

Pinging from remotedc1 to mydc2 and mydc1 shows an average time of 43ms...

What causes this kind of error?

Solution 1:

After some investigation, I found that a set of firewall rules was completely blocking communication between the site in question and the remote site, which happened to be the FSMO roles holder. Without the ability to talk to the FSMO masters, things started getting weird.

So, make sure if you run into this error that you double and triple-check that your firewall rules are not blocking communication between your domain controllers.

In our case, we were completely blocking all communication to the DC, so the non-smart-ass answer to your query @Iain is "all of them." Sorry I can't be more specific!