Secure Shell for Computer Science

Nick CzebiniakSung-Ho Maeung

What is SSH?

• SSH (Secure Shell) is a full replacement for rsh, rlogin, rcp, telnet, rexec, rcp and ftp

• Automatic authentication of users, no passwords are sent in clear text

• Secure remote login, file copying, and tunneling X11 and TCP connections( POP, IMAP, SMTP, HTTP )

When will I need SSH in CS?

• By June 18st 2001, telnet service will no longer be available on CS machines.

• Used to telnet into CS server from outside– Need SSH as a replacement for telnet, rlogin,

rsh

What SSH clients are available for PCs, Macs, and Linux ?

• SecureCRT: http://www.vandyke.co– 32bit version for Win98/98/2000/NT

• F-Secure: http://f-secure.com– Windows and Mac versions

• SSH Secure Shell: http://www.ssh.com– Excellent free SSH client for Windows and Linux

• TeraTerm Pro: http://www.zip.com.au/~roca/ttssh.html– A free SSH Client for Windows

• Mindterm: http://www.mindbright.se/mindterm/– A java based client for Windows and Mac

Secure Shell

How to connect?

• Hostname: tin.cs.rit.edu

• Username: abc1234

• Port Number: 22

Keys

SSH tunneling and Port Forwarding• Port forwarding• How to set up

– Depend on the SSH client you use.• ( SecureShell ) – www.ssh.com

– “listen port” – client port number• Ex) localhost:port#

– “destination host” – server address• tin.cs.rit.edu

– “destination port “ – server port number– “outgoing” and “incoming” tunnels

• need “outgoing” tunnels

Tunneling and Port Forwarding

Secure Shell

SSH on CS machines

• Located in .ssh2 directory

• Inside this directory– ssh-keygen2– Passphrase: ********– Again: *******– Public key saved– Private key saved

SSH on CS Machines

• Once setup, need to create identification and authorization files for ssh2– touch identification– touch authorization

• Edit these 2 files– Enter a private key in the identification file– Enter a public key in the authorization file

Conclusion

• Secure your data over the Internet.

• Secure your program over ftp.

• Use SSH service as soon as possible