- Kerberos is an authentication service – it takes the responsibility to prove your identity towards other “kerberised” services which would normally require your password.
Its most important function is to grant you access to the AFS (which contains your home directory, for example). You can obtain, view, and release Kerberos 4 tokens (which you need for the AFS) with the commands klog, aklog, tokens, and unlog. You will automatically get a token when you log in.
Kerberos 5 tickets (which are needed for certain other services, such as ssh login to another host) are managed with the respective commands kinit, klist, and kdestroy. Note that Kerberos tokens and tickets have a limited lifetime – they will only be valid for 25 hours. However, they will automatically be refreshed (at least on your local host) when you enter your password to unlock a previously locked screen.