Kerberos - KeyTab (Key Table)

About

All Kerberos server machines need a keytab file to authenticate to the KDC.

A keytab file contains one or more shared secret key.

A service will use a keytab file in much the same way as a user uses his/her password.

Default Location

/etc/krb5.keytab

Operating System

Windows

• Use the setspn command to map the Kerberos service principal name, HTTP/<host name>, to a Microsoft user account. An example of setspn usage is as follows:

C:\Program Files\Support Tools>
setspn -A HTTP/myappserver.austin.ibm.com myappserver

• Create a key tab with Kerberos - ktab

ktab.exe –k keytab-file-name –a [email protected]

(NB realm name must be specified in capitals).

Linux

To generate a .keytab file for a host computer that is not running the Windows operating system,

• Connect to the AD domain controller
• map the principal to the account and set the host principal password with ktpass

ktpass /princ host/[email protected] /mapuser Sample1 /pass MyPas$w0rd /out Sample1.keytab /crypto all /ptype KRB5_NT_PRINCIPAL /mapop set

• Merge the .keytab file with the /Etc/Krb5.keytab file on a host computer that is not running the Windows operating system.

Documentation / Reference

• Ktpass
• The keytab file