UNIX for Dummies Questions & Answers

Folks;
I have 2 SUSE DNS servers, one will be the master and one will be the slave. we normally update the master when adding any new servers to the DNS list.
I'm looking for a way to sync both servers every night, so the slave is updated nightly.
I thought of using "rsync" with cron to sync the directories but i couldn't find a way to add the password into the rsync command so it won't ask for the password.

Is there a better way than "rsync" and "cron" to sync both servers?

If not; here's what i use for rsync and hopefully someone can help me entering the password in this command line if possible.

currently i use this:

Code:

# rsync  -r  -a  -v  -e  "ssh -l  root"  remote_host_ip:/remote_directory/*   /local_directory

Thanks in advance