cctns:
You do not state in your post if the clients were visible before you made the changes to the host files for the clients and Master.
If these are new clients then add the clients to a backup policy as indicated above.
If these are existing clients who were previously available through host properties then check the changes you made to the etc/hosts files on the client and the master. It is important to remember that Netbackup uses hostnames to authenticate between Master/media and Clients. Each Entry should adhere to the following format:
ip address <tab> short name <tab> FQDN
From Admin Console>Host Properties>Client
Select client name in right pane. If the Master fails to connect the check hostname resolution
To verify hostname resolution run the following commands:
Windows:
Program Files\Veritas\Netbackup\bin
Unix
usr/openv/netbackup/bin
bpclntcmd -hn <server name>
bpclntcmd -pn < reverse lookup from client to master>
bpclntcmd -ip <server ip address>
The following documentation will assist you in troubleshooting client connectivity issues:
http://www.symantec.com/docs/TECH68832