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What is FTP, SFTP, Telnet and SSH?

SSH (Secure SHell) and SFTP (Secure File Transfer Protocol)

In short, use SSH wnen you need to securely login and interact with the command line on aremote server. Use SFTP when you want to securely transfer files to the remote server.

SSH (Secure SHell) is a protocol for remotely logging into a machine. Much like Telnet, an SSH client provides the user with a text session ("shell") on the remote machine. Unlike Telnet, SSH provides an encrypted connection between you (the client) and the remote machine (the server).

 SFTP (Secure FTP) is a replacement for FTP which provides an encrypted connection between the client and server for file transfers.

Why use SSH and SFTP?

To gain access to a remote server, you will need to send them your unique username and password. When connecting via Telnet or FTP, anyone who knows how to eavesdrop on your communication can easily find and use your usename and password. This is because Telnet and FTP transfer all information as plain text. Secure servers are setup to accept only SSH and SFTP so that your unique username and password are sent in an encrypted form that isnot be easily cracked.

Which to use, SSH or SFTP?

When logging into a remote machine, you should use SSH. This enables you to access the remote command line and enter commands, such as to create directories, move files, etc.

When simply transferring files into and out of a remote machine, you should use SFTP.

How to start using SSH and SFTP?


For Microsoft Windows, excellent options includde PuTTY and WinSCP. (See the Resources section for current download information.)

Macintosh OS X

OS X comes with SSH installed, and it is usually invoked from a Terminal window by typing the following command. (To run the Terminal application, go to: Applications>Utilities>Terminal)

ssh username@student.santarosa.edu

To transfer files while using Mac OS X, an excellent WYSIWYG applcation is Fugu. (See the Resources section for current download information.)

In OS X, a command line alternative for secure file transfers is to run the scp command in a Terminal window. To transfer a file from your Mac to a remoet, type the following command. In this example, you wold replace <file>, <username>, <remote-server> with the correct values.

scp <file> <username>@<remote-server.com>:<file>