OSSEC hosts can be centrally renamed by editing the etc/client-keys file.

However, since the client key also contains the host name the client will use, the keys must be re-extracted using manage-agents and the keys imported into the existing client installs.

This is only a small time-saving over removing and re-adding a client but less prone to human error.

This also works for changing OSSEC host IPs. Simply update them in the keys file and restart the agent and client and they will reconnect.