Remote access to the Intranet, and other UU restricted sites

A considerable part of www.cs.uu.nl is only easily accessible from the department's networks. Another related problem is that many restricted websites are only fully accessible from the UU IP number range (131.211.0.0). Examples are ACM, Springer and Siam.

Here is how you can access these sites using SSH and our http proxy service. (Note: another way to access sites like this is to use our VPN service)

The proxy service runs on one of the department's servers and relays http requests for www.cs.uu.nl and a few other restricted sites. This service is not accessible outside the department. Using SSH port forwarding, you can access the proxy service from a 'remote' computer. Your WWW requests are tunneled over the Internet to the proxy service, and the proxy server relays the requests to the appropriate www servers.
Because these requests come from a box with an IP address in the uu.nl (cs.uu.nl) number range, the server forks out the restricted pages. The proxy server then relays these pages back to you.

To make this work, you have to do two things:

• setup a forwarded port:
  
  Using UNIX:

  staff:

    ssh -v -L 3128:proxy.cs.uu.nl:3128 your_user_name@shell.cs.uu.nl
    

  students:

    ssh -v -L 3128:proxy.students.cs.uu.nl:3128 your_user_name@shell.students.cs.uu.nl
    

  Using Windows:

  You can set up PuTTY for port forwarding.

  This assumes that:
  • you can use 'ssh' to access 'shell.cs.uu.nl' (sunshine for staff) or 'shell.students.cs.uu.nl' (bellatrix for students). Instructions on how to set this up are here.
  • your 'local host' allows ssh port forwarding. Most systems do.

  You must use local port 3128, if you want to configure your browser using the 'auto config' described below.

• Instruct your browser to use the proxy for certain sites.

  For Netscape/Mozilla and friends and Internet Explorer, set 'proxy autoconfig' using the url

    http://www.cs.uu.nl/info/cs.pac
    

  Opera has a similar option under the Proxy settings.

  View the contents of the .pac file, to see which sites are directed to the proxy server.
  Copy and modify this file if you want to change the default port number.
  The mime type for this file should be application/x-ns-proxy-autoconfig.