Use the ktab command to manage the Kerberos keytab file
The Kerberos key table manager command (Ktab) allows the product administrator to manage the Kerberos service principal names and keys stored in a local Kerberos keytab file. With the IBM Software Development Kit (SDK) or Sun Java Development Kit (JDK) 1.6 or later, we can use the ktab command to merge two Kerberos keytab files.
To merge the ktab files, install Java Development Kit (JDK) Version 1.6 SR3 cumulative fix, which upgrades the JDK to Version 1.6.0_07.
To merge the ktab files, install Software Development Kit (SDK) Version 1.6 SR3 cumulative fix, which upgrades the JDK to Version 1.6.0.02.
To merge the ktab files, install Java Development Kit (JDK) Version 1.6 SR3 cumulative fix, which upgrades the SDK to Version 1.6.0 Java Technology Edition SR3.
Kerberos service principal (SPN) name and keys listed in the Kerberos keytab file allow services running on the host to validate the incoming Kerberos or SPNEGO token request. Prior to configuring Kerberos or SPNEGO web authentication, the WAS administrator must setup a Kerberos keytab file on the host running WebSphere Application Server.
Deprecated feature:
In WAS v6.1, a trust association interceptor (TAI) that uses the Simple and Protected GSS-API Negotiation Mechanism (SPNEGO) to securely negotiate and authenticate HTTP requests for secured resources was introduced. In WAS v7, this function is now deprecated.
- Configure and enable SPNEGO Web Authentication and filters on the WAS side using the console.
- Provide dynamic reload of SPNEGO without having to stop and restart the WAS.
- Provide fallback to an application login method if the SPNEGO web authentication fails.
depfeat
Important:
- It is important to protect the keytab files and make them readable
only by authorized product users.
- Any updates to the Kerberos keytab file using Ktab do not affect the Kerberos database. If we change the keys in the Kerberos keytab file, you must also make the corresponding changes to the Kerberos database.
The syntax of Ktab is illustrated later in this section by using Ktab with the -help operand.
$ ktab -help Usage: java com.ibm.security.krb5.internal.tools.Ktab [options] Available options: -l list the keytab name and entries -a <principal_name> [password] add an entry to the keytab -d <principal_name> delete an entry from the keytab -k <keytab_name> specify keytab name and path with FILE: prefix -m <source_keytab_name> <destination_keytab_name> specify merging source keytab file name and destination keytab file name
Following is an example of how Ktab is used to merge the krb5Host1.keytab file to the krb5.keytab file:
[root@wssecjibe bin]# ./ktab -m /etc/krb5Host1.keytab /etc/krb5.keytab Merging keytab files: source=krb5Host1.keytab destination=krb5.keytab Done! [root@wssecjibe bin]# ls /etc/krb5.* /etc/krb5Host1.keytab/etc/krb5.keytab /etc/krb5.keytab
Following is an example of how Ktab is used on a LINUX platform to add new principal names to the Kerberos keytab file, where ot56prod is the password for the Kerberos principal name:
[root@wssecjibe bin]# ./ktab -a HTTP/wssecjibe.austin.ibm.com@WSSEC.AUSTIN.IBM.COM ot56prod -k /etc/krb5.keytab Done! Service key for principal HTTP/wssecjibe.austin.ibm.com@WSSEC.AUSTIN.IBM.COM saved
Following is an example of how Ktab is used on a Windows platform to list Kerberos keytab file content.
[root@wssecjibe bin]# ./ktab
KVNO Principal
---- ---------
1 HTTP/wssecjibe.austin.ibm.com@WSSEC.AUSTIN.IBM.COM
[root@wssecjibe bin]# ls /etc/krb5.*
/etc/krb5.conf /etc/krb5.keytab
(dist) Tip: We can run the ktab command from the install_root/java/jre/bin directory.
(zos) Tip: We can run the ktab command from the install_root/java/J5.0/bin or install_root/java64/J5.0_64/bin directory.
Related concepts
Related tasks
Kerberos: The Network Authentication Protocol