Check the current replication health between the domain controllers.
Repadmin /replsummary

Displays the elements are remaining in the queue to replicate.
Repadmin /Queue

Displays the replication status when the specified domain controller last attempted to implement inbound replication of Active Directory partitions.
Repadmin /Showrepl

Forces the KCC (Knowledge Consistency Checker) on targeted domain controller(s) to immediately recalculate its inbound replication topology. It checks and creates the connections between the Domain Controllers. By running the command we are forcing DCs to check if new Domain Controller is found in the environment and if yes then add connection to the same.
Repadmin /KCC