On many systems, Kerberos is built into the login program, and you get
tickets automatically when you log in. Other programs, such as
rsh, rcp, telnet, and rlogin, can forward
copies of your tickets to the remote host. Most of these programs also
automatically destroy your tickets when they exit. However,
MIT recommends that you explicitly destroy your Kerberos
tickets when you are through with them, just to be sure. One way to
help ensure that this happens is to add the kdestroy command to
your .logout file. Additionally, if you are going to be away
from your machine and are concerned about an intruder using your
permissions, it is safest to either destroy all copies of your tickets,
or use a screensaver that locks the screen.