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Making an Initial Connection to i4 with SSH

What software should I use?

Mac OSX users may make a secure shell connection using the Terminal application found within the Utilities folder inside the Applications folder.

PC users should download PuTTY for Windows.

Logging on to i4 Using SSH

The machine, which provides shell access to the main NYU Web server, only supports secure shell (SSH) connections (not Telnet). In a SSH session, the information being sent back and forth (such as your password) is encrypted, so that if a mischief-maker intercepts your interactive login session, the data will be unreadable.

Connecting to

- For Mac OSX:
Open the Terminal application. At the prompt type:


where your_NetID above is your NYU NetID. Click the Return key to enter the information.

- For Windows:
Open the PuTTY application. For Host Name (or IP address), type:

where your_NetID above is your NYU Net ID. Make sure that the Port is set to 22. Click the Open button.

- For Linux/UNIX:
Open a terminal. At the prompt type:


where your_NetID above is your NYU Net ID. Click the Return key to enter the information.

Verifying Your Connection

The first time you connect to, you will be asked to verify the identity of the server by acknowledging the fingerprint of the server's key. Answering "yes" will save the server's fingerprint into a local known_hosts/cache file. If this fingerprint ever changes, ssh will prompt you with an error message regarding a possible "man-in-the-middle" attack.

Please see the following screenshots for examples of this verification message on each platform: Terminal (Mac OSX) screenshot | PuTTY (Windows) screenshot

Entering Your Password

Once you've agreed to accept the server's key, you will receive the prompt:


Enter your NetID password (the same password you use for NYUHome) and hit return. Note, you will not see your password displayed on the screen. Remember, when typing in your password, that the system is case-sensitive.

Agreeing to the Responsibility Statement

Once you've correctly entered your password, you will see the "Responsibilities of All New York University Computer and Network Users" statement. Read through the statement (hit the space bar to continue through the document) and at the end, enter "Yes or yes" if you agree ("Y" or "y" will not be accepted).

Next Steps

You should now be at the i4 system prompt. If you will not be using the i4 command line interface, you may now log out of the system. Type logout and hit the Return key to exit the system.

Planning to Use the i4 Command Line to Navigate?

You are always in a working directory. Your home directory is the working directory in which you find yourself when you log in.

The contents of a working directory may include files as well as other directories. When a directory contains other directories, it is often referred to as a parent, and the directories it contains are its children.

The arrangement (called a directory tree) is something like a family tree: each directory has a parent one level up from it in the tree.



In the example above, homework is the parent of file1, and smithj is the parent of homework. The pathname of a directory or file indicates its place in the directory tree, starting from the system's topmost directory (/), which is called the root directory.

Note that, in the pathname, the directory levels are separated by slashes (/). The directory /usr contains the home directories of smithj and other users.

On UNIX systems running at NYU, file names and directory names may be up to 31 characters long. When you first receive your account, your home directory will contain a few files which have been placed there by the system manager so that your account will operate properly. Normally, in a new account, the home directory will contain no further directories, but at NYU, there will also be a directory called bin, which is a receptacle for your personal executables and shell programs. Commands that you can use to create your own files and directories are our Common Command and Control Sequences section.