From LQWiki

sshd is the name of the daemon that implements the SSH protocol on a server. Typically sshd will spawn a shell for an incoming SSH client, or run a single command and return the output (if any). Many Linux systems use the OpenSSH daemon as a telnet replacement.

sshd, by default, listens on TCP port 22, though it will use a random high-numbered port for outgoing communications. You can also configure sshd to listen on a high-numbered port.

Typically ssh logins (and failed login attempts) are logged to /var/log/authlog. On many systems the sshd_config file can be found in /etc/ssh/