vSphere Web Client 5.1.x contains an option that binds vSphere Replication traffic to a specific vmknic.

Problem

If you use this option in vSphere Replication version 5.1.x and then upgraded to version 5.5.x, replication configuration fails due to the underlying connectivity issue.

Results

Manually edit the esx.conf to remove the incorrect tag value for the specific vmknic or reconfigure the tagged vmknic to be reachable by vSphere Replication. For details, see http://kb.vmware.com/kb/2066230.