XADM: Two Sites with the Same Organization and Site Name May Join Together (243398)

SUMMARY

When you have two multi-server sites with the same organization and site name and same service account, and you remove a server from one site and install it in the other site without deleting the server from the original site, the two sites will join together.

When this happens, you receive the following message on the server left in the original site:

Event ID: 1349
Source: MSExchangeDS
Type: Warning
Description:
The GUID on server ServerD has changed from 8ab25beb042fd311af6c00c04f68de18 ServerD to 54242885302fd311af6e00c04f68de18. This will cause all replicas to be resynced from scratch.

MORE INFORMATION

This behavior is by design.

When Exchange Server is removed from a server, you must delete it from the site so that all servers are notified that it was removed. The Remove All option in Setup does not do this. If the server is not removed, the remaining servers know the departed computer by name and will establish remote procedure call (RPC) connections to it as needed. Because they are in the same security context, there is no problem establishing a connection. Two sites with the same organization and site name have the same Naming Context (NC), so the information returned on a replication request is valid for the NC. When the two servers communicate, the remaining server sees that the GUID has changed on the moved computer. This cannot be used to decide against replication, however, because a server that is removed and reinstalled in the same site will also have a new GUID. There is no GUID for the organization itself, so Exchange Server cannot determine that an organization change has occurred.