Crossing Site Boundaries
Replicating the Active Directory (AD) database is an essential function of any Windows 2000 AD domain. Each domain controller (DC) maintains a copy of the AD database, so when a change takes place on one DC, the change needs to be replicated to all other DCs in the domain. Replication occurs automatically on a scheduled basis, but sometimes you must force a replication to register a change immediately on all DCs.

You can use the Microsoft Management Console (MMC) Active Directory Sites and Services snap-in to force replication to DCs within a site. Open Active Directory Sites and Services and find the server objects to which the change needs to be replicated. For each server object, double-click the object to open its Properties dialog box and go to the NTDS Settings tab, which shows all the AD connections between the server and other DCs. Right-click each AD connection to the DC on which the change was made, then select Replicate Now from the context menu. If the DC is in the same site, replication will occur immediately. But if the DC is in another site, a dialog box appears reminding you that the configured replication schedule between the selected server object and the DC controls when replication occurs. You can't use Active Directory Sites and Services to force replication in these situations.

The best tool I've found to force replication between DCs in different sites is Replication Monitor (replmon.exe), which you can find in the Win2K CD-ROM's Support Tools. (I prefer Replmon over repadmin.exe, which is also available in Support Tools, because Replmon lets you see both the DC objects and DC naming contexts.) Replmon lets you connect to multiple DCs from within one interface. This ability is important because in most forced replication situations, you want to be able to control replication to and from different DCs. After you use the tool to connect to a DC, right-click the DC's domain naming context and choose Synchronize This Directory Partition with All Servers to open the dialog box that Figure A shows. This dialog box offers three important options. The first option disables transitive replication, which replicates changes only to adjacent DCs in the replication topology. The second option lets you push replication from the DC with the changes to the other DCs. (In typical AD replication, DCs pull changes from the DC that has them.) The third option makes DCs in sites other than the replicating DC immediately eligible for replication, as long as they have a remote procedure call (RPC) connection to the DC that has the changes. Of course, for forcing replication between DCs in different sites, this third option is the most essential one to select.