Overview
To protect remote connections from hosts outside your network, transmissions can be encrypted. For Linux systems, you can use the Secure Shell (SSH) suite of programs to encrypt and authenticate transmissions, preventing them from being read or modified by anyone else, as well as confirming the identity of the sender. The SSH programs are meant to replace the remote tools such as rsh and rcp (see Chapter 15), which perform no encryption and include security risks such as transmitting passwords in clear text. User authentication can be controlled for certain services by Kerberos servers. Kerberos authentication provides another level of security whereby individual services can be protected, allowing use of a service only to users who are cleared for access.
