What is a Ticket?
Your Kerberos credentials, or "tickets", are a set of
electronic information that can be used to verify your identity. Your
Kerberos tickets may be stored in a file, or they may exist only in
memory.
The first ticket you obtain is a ticket-granting ticket, which
permits you to obtain additional tickets. These additional tickets give
you permission for specific services. The requesting and granting of
these additional tickets happens transparently.
A good analogy for the ticket-granting ticket is a three-day ski pass
that is good at four different resorts. You show the pass at whichever
resort you decide to go to (until it expires), and you receive a lift
ticket for that resort. Once you have the lift ticket, you can ski all
you want at that resort. If you go to another resort the next day, you
once again show your pass, and you get an additional lift ticket for the
new resort. The difference is that the Kerberos V5 programs notice
that you have the weekend ski pass, and get the lift ticket for you, so
you don't have to perform the transactions yourself.