This is not strictly true - the statement below should say "If using the
MIT KDC, there is no way to do this at the Kerberos level". The reason
is that our commercially supported KDC (TrustBroker Security Server)
supports this functionality you are asking about. Our secondary KDC
passes failed auth attempt count to the primary KDC so that this count
can then be incrementaly propagated to other secondaries. This means,
when using our product an account is disabled after a preconfigured
number of failed auth attempts regardless of which KDC (or KDCs) they
use to authenticate.


-----Original Message-----
From: [] On
Behalf Of Yu, Ming
Sent: 11 December 2007 02:03
Subject: Re: Account lockout support in Solaris 10 when


Thanks for the help.

That is th info I am looking for.


----- Original Message -----
Sent: Mon Dec 10 20:45:49 2007
Subject: Re: Account lockout support in Solaris 10 when authenticating

"Yu, Ming" writes:

> But I am still not clear how to "lock out" account after n-times of
> failed login.
> Are you saying there is no way to do it in current version of MIT
> kerberos?

Right, there's no way to do it at a Kerberos level. There are various
things that you can do within the service that's authenticating, but it
may require development on your part. (For example, if you're
authenticating the user via PAM, you could store the PAM failure count
somewhere and reject logins to that user once the failures reach a
particular threshold, something you could do without modifying anything
about how Kerberos works.)

Converting a failed authentication compromise into a denial of service
attack is generally a stupid idea, IMO. Far better to start rejecting
packets from a host that's apparently trying to do a dictionary attack.

Russ Allbery (

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