Securing Your Asterisk Server, Part 2 - page 2
Locking Down OpenSSH
A second way to tighten up remote SSH access is to use public-key authentication.
This protects your system passwords because you authenticate with a cryptographic
key, instead of using a login/password. (See Resources to learn how to do this.) In addition to disabling root logins, you should also
disable password authentication with this line in
Now you can sit back and laugh at brute-force SSH attacks, because they simply won't work.