Repadmin is the tool used to troubleshoot replication in an Active Directory forest.. commands like repadmin /replsum (to view replication summary) or repadmin /showutdvec (to view USN per domain controller).. are common commands.. it get’s tougher when we want to create or modify links during troubleshooting.. then we use /add to add replication links between two servers..
But aren’t replication links the what we see in Sites & Services?
Actually no.. the links are the actual replication agreements between the two servers, each partition of the AD has it’s own replication link per server.. to view them we can use repadmin: