2.3.7. Network logins
Network logins work a little differently than normal logins. For each person logging in via the network there is a separate virtual network connection, and there can be any number of these depending on the available bandwidth. It is therefore not possible to run a separate getty for each possible virtual connection. There are also several different ways to log in via a network, telnet and ssh being the major ones in TCP/IP networks.
These days many Linux system administrators consider telnet and rlogin to be insecure and prefer ssh , the ''secure shell'', which encrypts traffic going over the network, thereby making it far less likely that the malicious can ''sniff'' your connection and gain sensitive data like usernames and passwords. It is highly recommended you use ssh rather than telnet or rlogin .
Network logins have, instead of a herd of getty s, a single daemon per way of logging in (telnet and ssh have separate daemons) that listens for all incoming login attempts. When it notices one, it starts a new instance of itself to handle that single attempt; the original instance continues to listen for other attempts. The new instance works similarly to getty .