Locked Account

Very often I get tickets of accounts that keep getting locked out. When I check the logs all I get is that the service name Kerberos Authentication Service (krbtgt) is the one that is causing the issue. Recently I wanted to provide a user with more information and started looking at exactly what each error code meant, and I found the following table, I thought it was worth sharing it.

Result code	Kerberos RFC description	Notes on common failure codes
0x1	Client's entry in database has expired
0x2	Server's entry in database has expired
0x3	Requested protocol version # not supported
0x4	Client's key encrypted in old master key
0x5	Server's key encrypted in old master key
0x6	Client not found in Kerberos database	Bad user name, or new computer/user account has not replicated to DC yet
0x7	Server not found in Kerberos database	New computer account has not replicated yet or computer is pre-w2k
0x8	Multiple principal entries in database
0x9	The client or server has a null key	administrator should reset the password on the account
0xA	Ticket not eligible for postdating
0xB	Requested start time is later than end time
0xC	KDC policy rejects request	Workstation restriction
0xD	KDC cannot accommodate requested option
0xE	KDC has no support for encryption type
0xF	KDC has no support for checksum type
0x10	KDC has no support for padata type
0x11	KDC has no support for transited type
0x12	Clients credentials have been revoked	Account disabled, expired, locked out, logon hours.
0x13	Credentials for server have been revoked
0x14	TGT has been revoked
0x15	Client not yet valid - try again later
0x16	Server not yet valid - try again later
0x17	Password has expired	The user’s password has expired.
0x18	Pre-authentication information was invalid	Usually means bad password
0x19	Additional pre-authentication required*
0x1F	Integrity check on decrypted field failed
0x20	Ticket expired	Frequently logged by computer accounts
0x21	Ticket not yet valid
0x21	Ticket not yet valid
0x22	Request is a replay
0x23	The ticket isn't for us
0x24	Ticket and authenticator don't match
0x25	Clock skew too great	Workstation’s clock too far out of sync with the DC’s
0x26	Incorrect net address	IP address change?
0x27	Protocol version mismatch
0x28	Invalid msg type
0x29	Message stream modified
0x2A	Message out of order
0x2C	Specified version of key is not available
0x2D	Service key not available
0x2E	Mutual authentication failed	may be a memory allocation failure
0x2F	Incorrect message direction
0x30	Alternative authentication method required*
0x31	Incorrect sequence number in message
0x32	Inappropriate type of checksum in message
0x3C	Generic error (description in e-text)
0x3D	Field is too long for this implementation

Source: http://www.ultimatewindowssecurity.com/securitylog/encyclopedia/event.aspx?eventid=4768

I was able to find even more information in the Technet post:

http://technet.microsoft.com/en-us/library/bb463166.aspx