OpenSSH - Connect to and manage other machines.

Most people who use LInux or UNIX will usually recognise and use ssh quite commonly to connect to other machines and run updates or programs and generally monitor and control machines.

OpenSSH (the package including ssh) includes more than just ssh.

OpenSSH is a FREE version of the SSH connectivity tools that technical users of the Internet rely on.
Users of telnet, rlogin, and ftp may not realize that their password is transmitted across the Internet unencrypted, but it is.
OpenSSH encrypts all traffic (including passwords) to effectively eliminate eavesdropping, connection hijacking, and other attacks.

Additionally, OpenSSH provides secure tunneling capabilities and several authentication methods, and supports all SSH protocol versions.

The OpenSSH suite replaces rlogin and telnet with the ssh program, rcp with scp, and ftp with sftp.
Also included is sshd (the server side of the package), and the other utilities like ssh-add, ssh-agent, ssh-keysign, ssh-keyscan, ssh-keygen and sftp-server.


I often use ssh to connect to machines and run programs and backups etc...

SFTP is also useful ( a secure version of FTP) for transferring files.

The client side of ssh is installed with many Linux and UNIX OS's as it is now considered as an important program.

To connect to an ssh server you simply open a terminal and type:

bash$ ssh user@server-address

If the username on the server/ remote machine is the same as the current machine you can simply type:

bash$ ssh server-address

for example

bash$ ssh 192.168.1.2

or

bash$ ssh joebloggs@192.168.1.2

You could also use:

bash$ ssh 192.168.1.2 -l joebloggs

By default ssh uses port 22 so you may have to set this as an exception in your firewall.

You can however pipe ssh through another port with -p.

Also if the server IP is named in your hosts file /etc/hosts, you can then use the server's name instead of IP address.

For example:

bash$ ssh joebloggs@joebloggs-computer

The ssh help dialogue:

bash$ help ssh
usage: ssh [-1246AaCfgKkMNnqsTtVvXxY] [-b bind_address] [-c cipher_spec]
[-D [bind_address:]port] [-e escape_char] [-F configfile]
[-i identity_file] [-L [bind_address:]port:host:hostport]
[-l login_name] [-m mac_spec] [-O ctl_cmd] [-o option] [-p port]
[-R [bind_address:]port:host:hostport] [-S ctl_path]
[-w local_tun[:remote_tun]] [user@]hostname [command]



To set your machine up as an ssh server, to allow connections to your computer, you can simply install package sshd and set it to run as a DAEMON or at startup if your OS doesn't do it automatically.

People will have to know your password to connect to you computer so its quite secure.

Just make sure you use a good password.

(Resources at the top of this log are from: http://www.openssh.com/ )