X-Win32 and firewalls
The latest releases of X-Win32 (version 6.x and up) includes a Secure Shell (SSH) module that can be used to connect to skew3. To set this up, go through the following steps:
- Open X-Config and select "Wizard", select StarNetSSH as the connect method and click on the "Next" button.
- Type "skew3.kellogg.northwestern.edu" under Host name and click on the "Next" button.
- Type your login ID (if you do not provide a login ID, you can do so when you connect) and click on "Next".
- Under Host Command, select SunOS (Solaris). This will select "/usr/openwin/bin/xterm -ls" as the command to be executed upon login. Click on "Next".
- Provide a short name for the session. For example, call it "skew3ssh". Check "Launch this session now" to connect to skew3. Click on "Finnish".
- X-Win32 will open a dialog box prompting you for your password. Click on "OK" to connect.
Upon login, you will get an "xterm" window, such as the one below.
From this window, you may run the GUI version of software such as Stata (xstata), Matlab (matlab), or SAS (sas), among others. In some cases, you may want to run an ampersand to "free" your xterm prompt. This would be the case of Matlab and SAS (type "matlab &" or "sas &"). Please remember to exit both the applications and xterm sessions properly: select exit or quit from the application menu and logout from the xterm prompt. Do not exit applications by clicking on the "x" in the window's title bar.
SSCC users: You may download a registry key to configure sessions for seldon, hardin and mule (the latter is for access by IPR members, only). Save the key to your desktop and double-click on it to update your computer's registry settings. When you open X-Win32, you will see the three sessions configured.
The Northwestern license for X-Win32 restricts usage to connections that come from Northwestern IP addresses. If you have a high-speed connection at home, your cable modem service or DSL company assigns you an IP address that is not in the Northwestern domain. Using VPN software will enable you to use X-Win32 from a non-Northwestern high-speed connection.
For instructions on how to install and configure the necessary VPN software, refer to documents by KIS and NUIT:
If you have VPN configured and running, you need to change the IP address for display in X-Config to the IP address assigned by VPN to make X-Win32 work.
When the VPN is turned on, the VPN server automatically assigns an IP address for your computer, which is different from the IP address you obtained from your cable modem service or DSL company.
- You can find the VPN assigned IP address when you launch the VPN. In the VPN Client window, click on the "Logging" tab and make sure the "Log message level" is set to "Status". The last line then displays "The user connected with IP Addr ...". This is the IP addressed assigned to your connection by the VPN.
- Make a note of this IP address and go back to X-Config. Click on the "Display" tab and check "(proxy)". You will be prompted for a "proxy address". Type the VPN assigned IP address in the pop-up window, click OK and restart X-Win32.
If you have an active firewall on your workstation, X-Win32 will not be able to run. After a few minutes, instead of the skew3 login display you will see the following error message: "XDMCP: session failed" [...] "Cannot open display".
The X display protocol uses port 6000; whether you can turn this port on or not, depends on the specific firewall.
If you are using the Windows XP firewall, you may add port 6000:
- Right click on "Local Area Connection" and select "Properties" from the context menu.
- Click on the "Advanced" tab
- Click on the "Settings" button
- Click on the "Add" button. Type "X port" as a description of the service, your workstation's name (usually your department's acronym followed by your phone extension) under the name field, and type "6000" as external and internal port numbers. Click OK to make the addition effective.