Hi, I am doing mirroring for the first time. I have taken a backup restore from principal to mirror server. Then done the set of port using configuration database mirroring security wizard. When I tried to start mirroring, it is giving the following error. One or more of the server network addresses lacks a fully qualified domain name (FQDN). Specify the FQDN for each server, and click Start Mirroring again. The syntax for a fully-qualified TCP address is: TCP://<computer_name>.<domain_segment>[.<domain_segment>]:<port> I have taken a full backup and restore, trans log back up of principal to server also. Please help me with this. Regards, Swaroop.