Department of Engineering

Setting up a proxy server and using the CUED cache

Introduction

A WWW proxy-server gets WWW pages on behalf of your browser. This is useful if you want to isolate your machine from the outside world except for WWW access (which is the case for many CUED machines). The CUED WWW proxy-server currently acts as a cache too, saving time (and the University's money) if many peple access the same big file.

For general information on what caches/proxies do, see the CS's How to use the Web proxy server leaflet.

Setting up

By default, browsers on the CUED Teaching System use the proxy server. The notes below are mostly for people on research machines.

Automatic Configuration

• Firefox - Open the Preferences item in the Edit menu and choose the Network tab. Then click on the Settings ... button. On the Teaching System the System Defaults option option should be set, but even so, sometimes the proxy isn't used (and hence you can't contact the outside world) so you may need to set the Automatic proxy configuration yourself. Select the option, fill in the text field as shown below, press the Reload button then the OK button.
• Internet Explorer 7 -
  • Choose Tools | Internet Options
  • Choose the Connection Tab
  • Click on the button 'Lan Settings'
  • Click on the box marked 'Use automatic configuration script'
  • Fill in the address http://www-proxy.eng.cam.ac.uk/proxy-conf.pac
  • Click 'Ok' and then 'Ok' again to quit the Internet Options dialogue box.

Possible Problems

• If the proxy server stops working you won't be able to get any external files. In that case mail webadmin@eng.cam.ac.uk. Please provide whatever information you can about the symptoms of the problem and also which computer (or in which department or college) you saw the problem - the problem may not be affecting everyone.
• You can only use the CUED proxy if your browser is run from within CUED.
• Some documentation is licenced to be available only within the Cambridge domain. The proxy server should be configured to deal with such situations, but if you think that you're wrongly being denied access, mail webadmin@eng.cam.ac.uk with the URL(s) which fail, a description of what happened including any error messages, and the type of computer and web browser (including version number, if possible) that you were using.
• Engineering users not based on the Department's main site may sometimes need to set their browsers to fetch secure pages using a manual configuration. Setting the proxy to "www-proxy.eng.cam.ac.uk" and the port to 3128 for each of FTP, HTTP, and Security/HTTPS should work.
• To check your cache configuration use the university's Web cache test page