Important Note: The i4 server is no longer accepting requests for new accounts and active websites must be migrated before the scheduled retirement in July 2022.

Before you start working in i4, you must first make an initial connection using a secure shell (SSH) connection through Terminal or PuTTY. This one-time step is required regardless of whether or not you plan to work in i4 using an SSH file transfer protocol (SFTP) client.

Getting Started

The i4.nyu.edu machine, which provides shell access to the main NYU Web server, only supports SSH connections (not Telnet). In a SSH session, the information being sent back and forth (such as your password) is encrypted, so that if someone intercepts your interactive login session, the data will be unreadable.

On this page:

 

Recommended software

Duo Mobile

All users need to complete multi-factor authentication (MFA) through Duo Mobile to establish a connection to the i4 server. If you haven't done so already, enroll your device in MFA.

  • We strongly recommend that you use the Duo Mobile app with an iOS or Android device, including a phone or a tablet.
  • If you're unable to use the Duo Mobile app, then we suggest you access the i4 server from a computer near a phone number that you can enroll in MFA.

 

macOS

Mac users can make a secure shell connection using the Terminal application. Locate Terminal by navigating to Applications and then selecting Utilities, or by doing a Spotlight search.

Windows

Windows users should download the free, open source PuTTY application. PuTTY is a free implementation of SSH and Telnet for Windows and Unix platforms.

Connect to i4.nyu.edu

Using macOS

  1. Open the Terminal application.
  2. At the prompt type: ssh NetID@i4.nyu.edu
    Replacing "NetID" with your actual NYU NetID
  3. Click Return to enter the information.

Using Windows

  1. Open the PuTTY application.
  2. For Host Name (or IP address), type: NetID@i4.nyu.edu
    Replacing "NetID" with your actual NYU NetID
  3. Make sure that the Port is set to 22.
  4. Click the Open button.

Using Linux/Unix

  1. Open a terminal.
  2. At the prompt type: ssh your_NetID@i4.nyu.edu
    Replacing "NetID" with your actual NYU NetID
  3. Click Return to enter the information.

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Complete your connection

Verify server

The first time you connect to i4.nyu.edu, 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:

Enter your password

  1. Once you've agreed to accept the server's key, you will receive the prompt: Password:
  2. Enter your NetID password (the same password you use for NYUHome). Note: you will not see your password displayed on the screen. Remember, when typing in your password, that the system is case-sensitive
  3. Hit Return.

Complete authentication

  1. Immediately after you enter your NetID and password, you will be prompted to complete multi-factor authentication.
  2. When establishing a connection to the i4 server through SFTP clients you'll be required to authenticate through the Duo Mobile app on your mobile device, however your initial connection through SSH will allow you to select an authentication device.
  3. To complete MFA:
    1. Authenticate via the Duo Mobile app on your mobile device, or
    2. Select one of your available authentication methods by typing the appropriate selection number provided to you.
  4. If you don't authenticate within one minute, you won't be able to connect to the serve and will have to log in again. Note: some clients may have a shorter time out period.

Agree to the Responsibility Statement

  1. Once you've correctly entered your password and completed MFA, you will see the "Responsibilities of All New York University Computer and Network Users" statement.
  2. Read through the statement (hit the space bar to continue through the document).
  3. Write "Yes" or "yes" to you agree. Note: "Y" or "y" will not be accepted.

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Tutorial screenshots

For additional assistance, you can also review the tutorials for making an i4 connection with PuTTY and Terminal. These tutorials include screenshots alongside instructions for making a connection to the i4 server.

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 Return to exit the system.

Using 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.

Example:

/usr/smithj/homework/file1

In the previous example, 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.

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