There are certain Windows cmdlets and utilities that we can use for replication issue troubleshooting purposes. Among these, Repadmin.exe is the most commonly used Microsoft utility to troubleshoot AD replication issues. It is available in servers that have the AD DS or AD LDS role installed. It is also part of the Remote Server Administration Tools (RSAT). It is recommended to run this utility as a Domain Admin or Enterprise Admin. However, it is also possible to delegate permissions to only review and manage replication.
Microsoft also has a great little utility called Active Directory Replication Status Tool (ADREPLSTATUS), which allows us to review the replication status of an AD environment. We can download it via https://www.microsoft.com/en-gb/download/details.aspx?id=30005.
The following list contains the commands supported by repadmin...
