Authentication, in this context, means the act of proving who you say you are.
The way of doing this for most computer systems is to log in using the username and password that you have been allocated by the people who manage the computer you are using.
Since the username/password combination uniquely identifies you, it is essential you keep your password secure and confidential to you. If you suspect that someone has found out your password, you should change your password as soon as possible.
Please note: that both using another user's username and password and giving your own username and password to someone else are against the University's Regulations for the use of computer facilities.
When you log on in an open access computer room, your password is checked against the UOB domain (as indicated in the picture below).

A Windows domain is a way of organising computers and users; a user has a domain password which is used for all accesses to files and computers in that domain.
The UOB domain is a University-wide domain, in which all members of the University are registered at the same time as they register for a Bristol email address.
The UOB domain is the primary means of controlling computing access within the University.
Some of the reasons behind this are:
There have been a number of occasions when people who are not members of the University have been found using our facilities. This is unfair to members of the University, given the pressure on these resources. Requiring users to identify themselves when using these computers will prevent much of this abuse.
Occasionally members of the University are found to be misusing our computers and network. Requiring users to authenticate using a username and password will allow us to identify and take action against this type of anti-social behaviour. It is important, therefore, to log off when you have finished using the system, otherwise you may find that you are held responsible for someone else's misuse.
There are several network services that we cannot provide without authentication, such as central filestore and central printing. This service allows us to provide additional functionality for users of authenticating PCs.
Most computing areas within the University now use UOB domain authentication.
However, in some areas the departmental policy is that access to computers is restricted to members of certain departments only. In this case, you will see the somewhat obscure message "The local policy of this computer does not allow you to log on interactively." If you feel that this is in error, you should contact the department/ faculty who manage the computers concerned, who will be able to deal with the query.
A user's UOB domain account is created at the same time as their @bristol.ac.uk email address.
Undergraduates are automatically registered for email and the UOB domain, and their details are issued to them at registration.
Taught postgraduates are automatically registered for email and the UOB domain, and their details are issued to them at registration.
Research postgraduates are automatically registered for email and the UOB domain; they may collect their registration details from the Computer Centre help desk.
New staff are automatically registered for email and the UOB domain; they may collect their registration details from the Computer Centre help desk.
Staff who started before 4th May 2004 were not automatically registered for any computing facilities; they need to register online for computing facilities.
If the form says that you are already registered, but you do not know your password, please follow the procedures for if you have forgotten your password.
If you have forgotten your password, you will need to visit the IT Service Desk with your University identity card, and ask the staff there to issue a new one.
We regret that for security reasons we cannot issue passwords over the phone.
We have a document available which explains how to change your password.
Note that it takes up to five minutes for password changed to propogate to all our authentication servers (we use multiple geographically-distributed servers for authentication).
There are a number of reasons why you may not be able to log on, even if you think you're using the correct password. Here are some possibilities:






