GU Network Authentication Page


Users of this service must be members of the University of Cambridge who have agreed to abide by the rules of the Cambridge University Data Network (CUDN). You will need your Raven password to authenticate (more information below...). Your CRSID is recorded temporarily alongside the connections your computer initiates to other computers. We are required to do this in order to comply with the CUDN policy regarding computers using non-fixed network addresses.

Click if you are satisfied with these conditions of use.

Security Note: Be aware that if you are accessing this service from the Graduate Union wireless access point, your connection will not be encrypted. Thus it is up to you to make secure web connections (HTTPS) in preference to HTTP connections, and to use protocols like SSH and SFTP in preference to Telnet and FTP.

More information...

This service provides a means for the Graduate Union to allow members of the University of Cambridge to access the Cambridge University Data Network (CUDN). The rules on CUDN use agreed by the University's Information Technology Syndicate (ITS) require that the University Computing Service are able to track network abuses which are initiated within the CUDN back to their source. Rather than require registration of your computer on our network, we instead require that you prove who you are to us via Raven. We can then automatically acquire information to enable us to distinguish between the different users currently sharing our network resources.

The Raven authentication service has nothing to do with the Graduate Union. It is a facility run by the University Computing Service to enable any Cambridge organisation (such as the GU) to be assured of who you are, without requiring you to register a password with each individual such organisation. There is a great deal of further documentation on the Raven website at (you can access this site without needing to authenticate). If you successfully identify yourself to Raven, it will inform us you are who you say you are without us having to know your password. Nifty.

The ITS rules require us to not only log who you are when you start using our service, but also to maintain logs of what other computers you connect to via the CUDN (e.g. on the Internet). We only keep logs of this information for long enough to meet track abuses (probably something in the order of a few days). Note that we do not record any of the data you send or receive, just where it is going to or coming from. All institutions connected to the CUDN must be able to track abuses back to individual users - our need to log temporarily which computers you connect to is because otherwise from the CUDN perspective all your traffic appears to be originating from our server.

Future Plans

At the moment this system is still in a trial state. It is not guaranteed to be entirely stable and may self-destruct in interesting ways with little notice.

We are working to document our Cambridge-specific modifications to the open-source NoCat software (thanks to its authors for providing it free to the Internet!) which drives this service, and to fix remaining rough edges.

A pop-up window is currently used to keep your connection alive (otherwise you will need to re-login every five or so minutes). We recommend you allow pop-ups from * We will soon modify the NoCat system to only use pop-ups if they are requested by users rather than as the default mechanism to keep connections alive.

If the service starts using generating significant amounts of network traffic, we may need to introduce rate-limiting behaviour. We feel it is likely that the the GU will be able to afford to cover the cost of the Internet use made by users via this service.

We are planning to implement an alternative authentication mechanism by which frequent service users will be able to connect to the GU network without using Raven every time, at the cost of you having to do some manual configuration of your computer. Watch this space...

If you have any comments, problems, requests for this page to be clarified, new features to be added, etc, please contact Dave Eyers (