The assumption is that NBU will be down while IP address is being changed and that the system will be rebooted after the change. This means that your master will be 'good'.
As per above post - ensure correct forward and reverse lookup from media servers and clients.
You may have to clear host cache on media servers and clients:
NBU host cache is automatically cleared after 1 hour. See http://www.symantec.com/docs/TECH136792