SENS Timeshares

These systems are mainly intended for:

• Providing access to Unix applications to computers that cannot run them natively;
• Batch processing;
• Running programs that take a long time to run;
• Running programs that require more resources than can be found on a typical workstation;
• Providing services for remote users;
• Accessing public site printers; and
• Accessing a user's Engineering Unix home directory.

We ask that users not run more than one CPU intensive process on the timeshares at the same time. Also, the timeshares will be rebooted on occasion, usually the first week of the month, to install updates.

The policies for these systems are described on our timeshare policies page. We urge you to read that document prior to using our timeshare services.

The following instructions assume that the computer you are using is on campus and connected to the University network. Direct connections from computers outside of the local UB network are blocked. However, UB supports the Virtual Private Network (VPN) protocol, which allows for secure access from off-site systems. The UBIT Cisco Secure Client page has instructions on how to configure your computer to use the AnyConnect VPN software.

Microsoft Windows 11 comes with an implementation of OpenSSH that is installed by default. Please refer to the SENS Windows OpenSSH software guide for more information.

The PuTTY and VcXsrv software packages allow users of Microsoft Windows systems to use applications from remote Unix or Linux systems that use the X Window Protocol. Please see the PuTTY and VcXsrv software guides for more information on installing them.

Launch the PuTTY program from your program list (or desktop icon if you created it). When the following PuTTY Configuration screen appears do the following:

1. Select "Session" from the category list on the left side of the screen.
2. Enter linux.sens.buffalo.edu for the "Host Name"
3. Select "Connection" -> "SSH" -> "X11" from the category list on the left side of the screen.
4. Check the box for "Enable X11 forwarding" and for the "Xdisplay location" enter localhost:0
5. Select "Session" from the category list on the left side of the screen.
6. Under "Saved Sessions" enter SENS Linux and click the "Save" button.

You can repeat this process for the UB Unix timeshares. The process will be the same for that session but will contain the following changes:

• For UB Unix use ubunix.buffalo.edu for the "Host Name" and UB Unix for the "Saved Sessions" name.

1. Launch the VPN client from your computer and connect to the UB network (if connecting from off-campus).
2. Launch XLaunch from within the VcXsrv folder in program list (or desktop icon if you created it).
3. When VcXsrv starts take the default settings when prompted.
4. Verify that you see an X icon in your taskbar on the right side near the clock.
5. Launch PuTTY from your program list (or desktop icon if you created it).
6. Click on the session that you wish to connect to from your system (such as SENS Linux) and click Open.
7. If prompted about the host key for the server not being cached in the registry click Yes to trust the connection.
8. Enter your UB username and password at the prompts.

You should now be able to remotely run graphical software (such as MATLAB) on your system. If you wish to test the connection you can type "xeyes &" and a pair of eyes should appear on the screen (if they don't appear see if an icon is flashing in the taskbar or a window is minimized as it is probably hidden behind the window). Be sure to use the file menus of the programs to properly exit them and be sure to type exit at the prompt when you are done using the server.

The Terminal client and XQuartz software packages allow users of Apple Macintosh systems to use applications from remote Unix or Linux systems that use the X Window Protocol. The instructions below will help you install and configure the appropriate free software in order to use the SENS and UB Linux timeshares.

XQuartz is automatically installed on all SENS-supported Macintosh computers. For personally-owned and non-SENS-supported Macintosh computers, please refer to the SENS XQuartz software guide for information on installing it.

1. If connecting from off-campus, launch the VPN client from your computer and connect to the UB network.
2. Launch Terminal from Applications -> Utilities.
3. At the prompt type the following:
   • ssh -X username@linux.sens.buffalo.edu
     where username is your UBITName. Please note that in some cases you may have to use "-Y" instead of "-X", but this is less secure so avoid it if possible.
4. If prompted about the RSA key fingerprint type yes to continue connecting.
5. Enter your UB password at the prompt.

You should now be able to remotely run graphical software (such as MATLAB) on your system. If you wish to test the connection you can type "xeyes &" and a pair of eyes should appear on the screen (if they don't appear see if an icon is flashing in the taskbar as they are probably hidden behind the window). Be sure to use the file menus of the programs to properly exit them and be sure to type exit at the prompt when you are done using the server.

If you wish to connect to the UBUnix timeshares the process will be the same, except that in step 3 you should use "-Y" instead of "-X" and "ubunix.buffalo.edu" as the host name:

$ ssh -Y username@ubunix.buffalo.edu

To establish a standard command line connection from a Unix or Unix-like system, including Linux and macOS, type:

$ ssh linux.sens.buffalo.edu

If you intend to use X Window System graphical applications, use this command instead:

$ ssh -X linux.sens.buffalo.edu

You should now be able to run X Window applications. For a simple test, type "xcalc" at the timeshare prompt and a calculator should appear.

For some software applications, such as MATLAB, the above command line may not work; in such cases, use this line instead:

$ ssh -Y linux.sens.buffalo.edu

If neither of those methods work, you will need to set the X Window display settings manually. First, determine the network name or the network (IP) address of your computer. Then, on the timeshare, type a command such this, replacing "computername.somedomain.buffalo.edu" with the name or network address of the computer you are using:

setenv DISPLAY computername.somedomain.buffalo.edu:0.0

Next, find out the name of the timeshare you are using:

$ uname -n

You must now tell your computer's X Window server that it is allowed to reply to connection requests from the timeshare. If you are on a Unix, Linux, or macOS system, open a new command window and type the following (replace "dracula" with the name of the timeshare to which you are connected):

$ xhost +dracula.sens.buffalo.edu

You should now be able to run graphical software such as MATLAB using commands such as "use matlab".