Contest Systems Overview
Connectivity Guide

Operating System Services

z/OS has various services that you will be connecting to during the course of the contest. These services are listed below along with corresponding port numbers for client connectivity. You may need to communicate the following information to your network administrator to ensure the following ports and services are available:

z/OS IP Address :
Service Port
3270 23
SSH 22
FTP 21
RDz (Optional) 4035

Contest Environment

In recent years, the contest environment had multiple operating systems for you to connect to. This year, we are only using z/OS. However, you will be using two different clients to communicate with different operating environments inside z/OS. The different environments are:

  • z/OS Multiple Virtual Storage (MVS)
  • z/OS Unix System Services (USS)

z/OS is running as a virtual machine on a single physical z13 at the z/ISV Lab in Dallas, TX.

Note: Since the Dallas Data Center is a lab environment, the running systems are subject to regular scheduled maintenance outtages. During a regularly scheduled interval, the z13 that hosts the Master the Mainframe contest is unavailable.

Click here to view the outage schedule.

Next: Required Workstation Software

Required Workstation Software
Connectivity Guide

The contestant must install various software depending on the workstation's operating system. Please see the section below that corresponds to your workstation.


The following software is required for contestants running Linux workstations.

  • x3270

    Refer to your respective Linux workstation distribution's repository to acquire and install x3270. If you are unsure of what the previous sentence means, use your favorite search engine to search for something like “Ubuntu 16.04 x3270 installation” or “Fedora 24 x3270 installation”. Once installed, you can open the 3270 emulator from the local terminal by entering the command x3270 or by searching the application menu.

  • OpenSSH

    In general, OpenSSH is installed by default into Linux. Test this by opening a local terminal session and entering the command ssh.


The following software is required for contestants running Mac workstations.

  • tn3270

    Brown University provides a tn3270 client that is freely-licensed for non-commercial use.

    Download it from here:

    Select the tn3270 release that supports your OS X version. Most Mac users will select the latest 3.4.0 release as it supports OS X 10.3.9 and later.

  • OpenSSH

    In general, OpenSSH is installed by default into Mac OS X. Test this by opening a local terminal session and entering the command ssh.


The following software is required for contestants running Windows workstations.

Next: Connection Instructions

Connection Instructions
Connectivity Guide

Connecting to z/OS tn3270

  • Workstation is Linux: use x3270

    To connect to z/OS tn3270 (TSO, ISPF, etc) from a Linux workstation x3270 client, first start the client. From a console command line, run “x3270”. This opens a new x3270 session window.

    Ensure that your client is set to "Model 4". Click Options -> Screen Size -> Model 4 (80x43).

    Click Connect at the top and in the "Enter Hostname" box, type in IP address for z/OS.

    Linux workstation x3270 client

    Then click Connect.

    At this point, you can rest assured that the connectivity to z/OS is functioning properly. Refer to the Part One challenge documentation for instructions on how to log onto z/OS.

  • Workstation is Mac: use Brown tn3270

    Navigate to the folder that contains the tn3270 software and double-click the tn3270 X icon to start tn3270. You may see a prompt about the application being downloaded from the internet. Select Open.

    In the new window, enter the IP address for the contest z/OS system as the hostname and a Window Title of your choosing.

    Click on "Screen Format" and set the "Large Screen Size:" option to 43x80 (Model 4). Then click Okay.

    Select Open Connection. It make take a few seconds for the z/OS or z/VM welcome screen to appear. Once you see this screen, congratulations, you are connected!

  • Workstation is Windows: use Vista tn3270

    Start Vista tn3270 and click File -> New Session Ask

    In the Host IP Name or Alias box, enter the IP address of the contest z/OS system.

    Click Connect. Once you see the following screen, you've successfully connected to z/OS.

  • Configuring Vista tn3270 for Model 4 (Mod 4)

    To change Vista tn3270 to a model 4 display, click Options -> Options.

    Next, select the Display tab at the top and click the Mod 4 radio button.

    After clicking Okay, Vista tn3270 should prompt you for a reconnect. Click OK.

    Once logged back into z/OS, you'll note the screen resolution has increased.

Connecting to z/OS SSH

  • Workstation is Linux: use ssh

    From a local terminal, run the command ssh USERID@ The first time you connect you will be prompted to verify the authenticity of the host. Enter “yes” to continue connecting.

    You will be greeted with the following screen.

    At this point, you can rest assured that SSH connectivity to z/OS is functioning properly.

  • Workstation is Mac: use ssh

    Use the same instructions as to connect from Linux; these should work in Mac.

  • Workstation is Windows: use PuTTY

    After starting PuTTY, enter the IP address of the contest z/OS system in the Host Name (or IP address) box. Ensure that the port is set to 22 and the SSH option is selected. Then enter MTM-Unix in the Saved Session box and click Save.

    The next time you start PuTTY, you can just double click the newly created Saved Session "MTM-Unix" to quickly reconnect.

    Click on the Open button at the bottom.

    The first time you connect to z/OS Unix, you will be see a Security Alert. Click Yes to continue.

    Enter USERID at the 'login as:' prompt to test the connection.

    If you are prompted for a password, you are ready to connect to the z/OS USS contest environment. Well done!

Note: During Part One of the contest, you will be setting your password in ISPF. This is the same password that you will use to authenticate to USS.

Next: Part One - Welcome