Kerberos AS-REQ

mark mark at mproehl.net
Fri May 14 11:18:43 EDT 2010


Hi,

you can get tickets for any service principal by sending a AS-REQ with
kinit. By default kinit requests TGTs (i.e. service tickets for
krbtgt/REALM at REALM). -S overides this behaviour. So "kinit -S 
HTTP/server.domain at REALM"
should just get you an initial service ticket for the HTTP service on
server.domain instead of a TGT.

If you just want to check if the KDC can issue service tickets for
HTTP/server.domain by TGS-REQ, you can use "kvno HTTP/server.domain"
after doing a kinit.

I wonder why the server name in your wireshark is written lowercase
(http/server.domain instead of  HTTP/server.domain). Could that be the
reason for PRINCIPAL_UNKNOWN error?

Regards,

Mark Pröhl

On 05/14/2010 04:38 PM, Yang Li wrote:
> When I run Kinit -S HTTP/server.domain.  KDC returns with PRINCIAPL_UNKNOWN
> error.
>
>
> >From WireShark, I can see client makes a (KRB 5 )AS-REQ to KDC, but its
> KDC_REQ_BODY has the server name (principal) as http/server.domain. is this
> the right behavior? should client sends krbtgt/domain in its request to KDC
> instead? My understanding is the purpose of AS-REQ is only to get TGT? can
> someone help me understand this?
>
> Thanks, -Yang
>
>
>
> -----Original Message-----
> From: Tom Parker [mailto:tparker at cbnco.com] 
> Sent: Wednesday, May 12, 2010 1:40 PM
> To: Yang Li
> Cc: 'Russ Allbery'; kerberos at mit.edu
> Subject: Re: error message after kdestroy
>
> klist should always fail after a kdestroy
>
> kinit should work fine to get you a new TGT
>
> On 05/12/2010 01:32 PM, Yang Li wrote:
>   
>> Thanks Russ for your response.
>>
>> What puzzle me is, this behavior is not consistent. Most of time, after
>> kdestroy, either klist or kinit can still get TGT ticket, but i did get
>>     
> the
>   
>> error message sometimes after kdestroy, is that odd?
>>
>> Thanks, -Yang
>>
>>
>>
>>
>> -----Original Message-----
>> From: kerberos-bounces at mit.edu [mailto:kerberos-bounces at mit.edu] On Behalf
>> Of Russ Allbery
>> Sent: Wednesday, May 12, 2010 12:43 PM
>> To: kerberos at mit.edu
>> Subject: Re: error message after kdestroy
>>
>> "Yang Li" <sharepointlink at hotmail.com> writes:
>>
>>   
>>     
>>> after kdestroy command, i get the following error message on any other
>>> commands such as klist or kinit. Any idea?
>>>     
>>>       
>>   
>>     
>>> No credentials cache found while getting default ccache
>>>     
>>>       
>> Well... yes.  kdestroy destroys the credential cache, so the other
>> commands now no longer have a credential cache to work with.  That's the
>> whole point of kdestroy.
>>
>>   
>>     
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