Kerberos authentication with Active Directory

Question

I have tried using JAAS to authenticate to MS Active Directory and keep getting "javax.security.auth.login.LoginException: Pre-Authentication Information was invalid"
I have tried authenticating with multiple user accounts and on three different realms (Active Directory domains).
How do I need to format the username? I know that when using JNDI to access Active Directory I have to use the format "[email protected]" or the RDN. I have tried it both ways with JAAS kerberos authentication as well as with just the username by itself. I don't think that the username format is the problem though because if I set the account lockout policy to 5 failed attempts, sure enough my account will be locked out after running my code 5 times. If I give a username that doesn't exist in Active Directory I get the error "javax.security.auth.login.loginexception: Client not found in Kerberos database" Is there something special that I have to do to the password?
I know that there is just something stupid that I'm missing. Here is the simplest example of code that I'm working with:
import java.io.*;
import javax.security.auth.callback.*;
import javax.security.auth.login.*;
import javax.security.auth.Subject;
import com.sun.security.auth.callback.TextCallbackHandler;
public class krb5ADLogin1 {
public static void main(String[] args){
LoginContext lc = null;
try {
lc=new LoginContext("krb5ADLogin1", new TextCallbackHandler());
lc.login();
catch(Exception e){
e.printStackTrace();
Here is my config file:
krb5ADLogin1 {
com.sun.security.auth.module.Krb5LoginModule required;
The command I use to start the program is:
java -Djava.security.krb5.realm=mydomain.com
-Djava.security.krb5.kdc=DomainController.mydomain.com
-Djava.security.auth.login.config=sample.conf krb5ADLogin1

Answer 1

Hi there ... the Sun web site has the following snippet:
http://java.sun.com/j2se/1.4/docs/guide/security/jgss/tutorials/Troubleshooting.html
+ javax.security.auth.login.LoginException: KrbException::
Pre-authentication information was invalid (24) - Preauthentication failed
Cause 1: The password entered is incorrect.
Solution 1: Verify the password.
Cause 2: If you are using the keytab to get the key (e.g., by
setting the useKeyTab option to true in the Krb5LoginModule entry
in the JAAS login configuration file), then the key might have
changed since you updated the keytab.
Solution 2: Consult your Kerberos documentation to generate a new
keytab and use that keytab.
Cause 3: Clock skew - If the time on the KDC and on the client
differ significanlty (typically 5 minutes), this error can be
returned.
Solution 3: Synchronize the clocks (or have a system administrator
do so).
Good luck,
-Derek