Sshd

sshd is the Secure Shell Daemon, the "server" program that allows ssh logins to your system. The config file is usually located in /etc/ssh/sshd_config (watch out for those underscores) and it's part of the base system.

In the configuration of sshd, you should restrict it to use only protocol version 2, as there have been insecurities found with sshv1.

Also using ssh keys instead of just passwords can be an extra level of security.

See also

ssh

sshd_conf

ssh keys, creating

ssh keys, using

SSH:_Passwordless_authentication