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Ssh Introduction Nature is no longer allowing telnet connections. Telnet is prone to numerous security holes that we have all been painfully made aware of over the last several years. The end result of using telnet for a system with the number of users currently on nature is that it is just a matter of time before we have the entire system compromised again. We'd be forced once again to have everyone change their passwords. Our best recourse is to minimize and evenutally elimiate all attempts to log into nature using weak methods (e.g. telnet, ftp, plain POP (non APOP), rlogin, rsh, etc.) Terminal-based (i.e. telnet-like) access to nature is still possible, but is now accomplished using the "Secure Shell Protocol", or SSH. SSH SSH provides the user with secure login connections over untrusted networks. SSH terminals act as a replacement for the telnet protocol. To ensure any connection to the server is safe, SSH uses... cryptographic authentication. a complex, dual key exchange system, so no one can pretend to be you automatic session encryption once a secure connection is made to the server, all transmitted data is encrypted and useless to anyone who doesn't have the right keys Integrity protection methods numerous methods to ensure that the link remains safe and cannot be compromised at any time during the communication between the client (you) and the host (nature) SSH login example (Example assumes your account name on nature is "safeuser") otheruser@notnature:~>ssh nature.berkeley.edu -l safeuser safeuser password: (you enter your password here) Last login: Mon Oct 25 1999 15:16:33 from notnature.Berkeley.E Sun Microsystems Inc. SunOS X.X Generic August 1997 No mail. Erase set to backspace. Kill is control-U (^U). Interrupt is control-C (^C). safeuser@nature:~ % Hold On! What if I am on a computer that doesn't have SSH and I want to get access to nature? Now what are my options?

One touch of nature makes the whole world kin.
                                  --Shakespeare