Here are the design considerations when evaluating a Preferred Bridgehead Server for multi-site deployments of Active Directory:
- It is best practice to have more than one bridgehead server per site.
- But if you want to “control” or “manage” site-to-site-replication, you must only choose one preferred bridgehead server.
- If replication fails in a 3+ site environment, and there are preferred bridgehead servers, change the bridgehead server. Non-fully IP Routable networks may require another (non problem) site to replicate to and the failed PBHS may reside there
- To avoid single point of failure with PBHS, you need to either have multiple PBHS at each site, or NONE – but this will reduce management.
- If poor performance on a DC (which is also an app server) make another DC the PBHS, typically the RRAS DC if there is one.
- Use PBHS for controlling replication traffic, not GC
- PBHS can be configured for IP and/or SMTP (seperately)
- Use IP by default, SMTP for unreliable connections
- SMTP requires a Enterprise Certificate Authority (ECA)