Users run passwd to change their passwords.
$ passwd username
Before users can change their passwords, you must start the rpc.yppasswdd daemon on the master server to update the password file.
The rpc.yppasswdd daemon starts automatically on the master server. Notice that when the –m option is given to rpc.yppasswdd, the make command is run in /var/yp immediately following a modification of the file. If you want to avoid having the make command run each time the passwd file is changed, remove the –m option from the rpc.yppasswd command in the ypstart script and control the pushing of the passwd maps through the crontab file.