We are aiming towards a single College password for each user, that allows you to access all standard university and Departmental services, such as email, remote login and web services. Currently, all CSG-maintained Linux systems in the Department accept your College password (actually a Kerberos password stored in the College Active Directory domain).

DoC Windows machines currently use their own separately-stored passwords - however changing your College password via ICT's password change webpage attempts to also set your DoC Windows password.  So usually, your College and DoC Windows passwords will be the same. Sometimes the synchronization fails, and you may need to manually change your DoC Windows password to be the same as your College password.

Kerberos also provides the ability to use ticket-based automatic single sign-on across services that have been extended to support it. When you login to (or unlock a locked session on) a DoC Linux machine, you receive a Kerberos ticket that lasts 8 hours. All the following services will try your current ticket rather than asking you for your password again until your ticket expires after 8 hours:

  • Remote login via Secure Shell (SSH);
  • Departmental web pages accessed over HTTPS from Kerberos-aware browsers like Firefox;
  • Network filesystem access via Windows Networking (SMB/CIFS) - but this uses your DoC Windows AD/Kerberos ticket.

When your ticket has expired, you can give yourself another ticket from the College Kerberos/AD servers either by screen locking and unlocking your Linux session, or via the Linux command:

kinit xyz13@IC.AC.UK

[if your username is xyz13].

Note that "IC.AC.UK" must be written in upper case as shown, it's not an email address, it's a Kerberos realm. If you're having trouble logging in to any service, this is a really good test command to run, as it provides specific error messages in the event that something unusual has happened, such as your account being locked.


Assuming that you know your current College password, you can change your College password either by:

kpasswd xyz13@IC.AC.UK


Please note that College passwords must be changed at least once a year, if you receive an email saying you need to change your College password in the next few days, take it seriously and do so. Do not ignore it or your account will get locked out and you will need to visit the ICT Service Desk in person to get it unlocked.


If you have been granted super-user access to a machine, you will have a 'root principal' with a different password to your main accounts. You can change it from the Linux command line:

kpasswd xyz13/root@DOC.IC.AC.UK


Assuming that you know your current password, either:

  • Log in, press CTRL-ALT-DELETE, and select 'Change password'.
  • from the Linux command line:
kpasswd xyz13@WIN.DOC.IC.AC.UK


If you can't remember your College password, choose from these options:

  • come to the CSG helpdesk (room 305 Huxley) with your swipe card and ask us to let you change it.
  • go to the ICT service desk (level 1 - Central Library) and ask the same.
  • email (eg. when abroad). Provide sensible info, eg. your username, your CID and they'll usually allow a password reset.

  • contact the ICT service desk on x49000 (i.e. 0207 594 9000).

If you can't remember one of your DoC passwords, come to the CSG helpdesk (room 305 Huxley) with your swipe card and ask us to let you change it.