KeyTab / Kerberos Key Table

Keytab files (/etc/krb5.keytab, for example) are used to securely identify a item or group of items. For instance, in the NssQidb system, they are used to ensure that hosts that are authenticating are from the correct subnet.

You can view the contents of a keytab file if you wish (if you have access to read the file):

klist -k /etc/krb5.keytab

This will show you the contents of the file. For example:

anc:~$ klist -k ldap.signals23.keytab 
Keytab name: FILE:ldap.signals23.keytab
KVNO Principal
---- --------------------------------------------------------------------------
   4 ldap/signals23.bu.edu@AD.BU.EDU

This key file is saying that signals23.bu.edu has trust to use the LDAP service via the computer account signals23.bu.edu on AD.BU.EDU.