Accessing BlueBEAR using PuTTY and Exceed

We provide access to GUI applications and the BlueBEAR GUI through the BEAR Portal and this is the suggested method for accessing such applications. Note that PuTTY is only required for Windows systems – macOS and Linux users can instead use their included terminal applications.

Downloading and Installing PuTTY

From a University-owned machine:

Go to the Software Centre (see KB11882) and search for "putty" via the Application search field (at the top-right of the page). This will allow you to install PuTTY without requiring administrative privileges.

From your own computer (requires administrative privileges):

Obtain the PuTTY Windows installer (not the standalone putty.exe) from the PuTTY download site; the installer has the name putty-version-installer.exe, where version is the version number. Following installation, PuTTY will be available from the PuTTY program group.

Installing, Configuring and Running Exceed

If graphics is not required then this section may be skipped.

Exceed and Exceed3D are available on site license from Software Sales and can be downloaded by going to (N.B. you'll need to log-in using your University credentials). When Exceed v14 or higher is installed it creates a program group Open Text Exceed version-number, for example Open Text Exceed 14. This will be referred to as the OpenText Program Group in this note. Earlier versions will have a different Program Group for Exceed, probably involving Hummingbird Connectivity.

We are aware of multiple users who have had issues using newer applications, especially those based on the GTK+ version 3 toolkit, with older versions of Exceed.  Please make sure you are running the latest version before reporting a fault to us.

Exceed is configured using the Xconfig program, found in the OpenText Program Group/Exceed Tools group. The first step in configuring Exceed is to set the security options. Since PuTTY uses X tunnelling, described later, it should be set to disallow any direct calls from external hosts. To do this, go to the Security, Access Control and System Administration section from the Xconfig page and select the No Host Access radio button in the Security/Host Access Control List section. Select the large green tick (Validate and Apply Changes) from the Xconfig toolbar at the top of the Xconfig window. Next select the Network and Communication tabbed sheet and select the Passive mode. Select the large green tick (Validate and Apply Changes) from the Xconfig toolbar at the top of the Xconfig window.

Exceed3D is required for applications that use OpenGL graphics, and should always be installed since it has no adverse impact if it is not required. Exceed3D is installed after installing and configuring Exceed.

Run Exceed3D by clicking Exceed in the OpenText Program Group when an Exceed icon will appear in the taskbar; no other output apart from the splash screen at startup will be given. Exceed3D is now running, ready to provide graphical support to Unix applications when required.

Configuring PuTTY

Running PuTTY from the PuTTY program group will open a display similar to the following:


Specify as the Host Name, specify bluebear in the Saved Sessions field and select Save. This will enable the session named bluebear to be loaded for subsequent uses of PuTTY for non-graphical use of the cluster.

PuTTY needs to be configured to expect the correct character set that is used on BlueBEAR; without this there may be problems with displaying non-alphanumeric characters, and some programs expect to find a particular character set. Open the Window/Translation page and select UTF-8 as the Remote Character Set:


Next open the Connection/Data page and under Environment Variables put LANG in the Variable box and en_GB.UTF-8 in the Value box:


then click Add

Open the Session page, ensure that bluebear is still shown in the Saved Sessions box and select Save

Some networks may drop the session if no data is transferred in either direction after a certain time interval. If sessions are closing unexpectedly (most often with a Connection reset by peer or similar message) after they have been idle for a while, it may be worth specifying an interval for PuTTY to send data through the session at regular intervals in a way that does not disrupt the actual terminal session. If there is not a problem with sessions closing unexpectedly then the following change should not be made, since it can introduce other problems depending on the type of network.

To send these keep-alive messages open up the Connection menu and specify a value in the Seconds between keepalives field; in this example an interval of 10 minutes (600 seconds) has been specified:


Open the Session page, ensure that bluebear is still shown in the Saved Sessions box and select Save

If graphical applications are to used, PuTTY needs to be told to forward graphical commands to the X server. To do this, open the Connections/SSH/X11 page:


and select the Enable X11 forwarding check box. Re-open the Session tab, ensure that bluebear is still shown in the Saved Sessions box and select Save.

Open a connection to bluebear with the Open button at the bottom of the page, or by double-clicking on the session name (bluebear in this example). The first time that PuTTY is used to connect to a server from a PC a prompt asking if you want to save the key is given. Accept the key and the logon prompt is given - subsequent logons to bluebear from the same PC will lead directly to the logon prompt. After logging on to BlueBEAR, ensure that Exceed is running by observing the Exceed icon in the taskbar; if not, double-click OpenText Program Group/Exceed, and an Exceed icon will appear in the taskbar; no other output will be given.

Issue the xclock command and a clock should appear on the monitor. Note that sometimes the clock will appear under other windows, so you may need to mimise the active window before you see the clock.

Common Problems

When you run a graphical application you may encouter the following errors:

List of possible errors
Error: Can't open display:
This means you have not ticked Enable X11 forwarding checkbox in PuTTY.
PuTTY X11 proxy: unable to connect to forwarded 
X server: Network error: Connection refused
Error: Can't open display: localhost: 27.0
This means Exceed is not running.
XDMCP has timed out, no response from XDMCP
If you see this error, follow this procedure:
Launch Exceed, then right-click on its taskbar icon and launch Xconfig. Choose "Communication" and change the "Mode" to "Passive". Click "Save".
Xlib: extension "MIT-SHM" missing on 
display "localhost:21.0".
This means you need to enable MIT-SHM in Exceed. Launch Xconfig, navigate to X Protocol, Extensions and then place a checkmark beside MIT-SHM, and hit Save.


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