Hi again,

I did a quick test, and you do need the the remote domain and its admin server 
defined in your kerberos conf file for kadmin to work. So the '-s' option 
appears to be redundant :( .

Moral, get your kerberos configuration right.

Jeremy



Jeremy Hunt wrote:
>
> Hi people (I am not too sure who I am talking to, probably Matt),
>
> I don't think what I described was cross-realm authentication. It is more 
> like running a client program to connect to a remote server.
>
> kadmin is a client program. With my suggested arguments you are telling the 
> kadmin program to use a kerberos domain (or realm if you prefer), and you are 
> telling it to use a kerberos principal and a specific key table file. As a 
> client program it will read your krb5.conf file and lookup the admin server 
> for that realm (or domain if you prefer that term) and it will look for the 
> named principal's key in the specified key table file. If all is correctly 
> configured it should connect to the port kadmind is using on the remote 
> machine, using the realm the remote machine administers and using the correct 
> key with a matching principal name to authenticate itself.
>
> Under those conditions you could use the kadmin client program on a machine 
> that did not otherwise have kerberos installed. I see it as using a mail 
> client like 'seabird' to connect to a gmail.com account, most people can do 
> that whatever internet domain they are running the mail client on.
>
> I think cross-realm authentication is a little trickier than what I describe 
> and what I thought you were attempting. Do you need cross-realm 
> authentication and if so why? If all you want to do is administer a remote 
> system then I do not think it is worth the trouble. If you have to link the 
> two realms for some reason other than you want to administer them from the 
> same machine, then you would consider it.
>
> I hope this clarifies things,
>
> Jeremy Hunt
>
> PS: Note that in my first reply I purposefully used a different keytab file 
> for the remote realm because I don't think there is a way to export the key 
> into a file without generating a new version number. Without looking at the 
> code or more simply testing I cannot guarantee that joining two keytab files 
> with something like 'cat' will work.
>
> PPS: I also note there is a '-s' argument to the kadmin program. This defines 
> both the remote server machine and the kadmind port. so you might not even 
> need your configuration file set up correctly for it to work. Try it. :)
>
> [email protected] wrote:
>> Hi Jeremy,
>>
>> Thank you for your answer.
>> From your point 4 ('If the entry for admin/fqdn2 is not in the keytab 
>> admin.fqdn1, then copy the keytab admin.fqdn2 to your local system'), I 
>> deduce that we can do cross realm authentication with kadmin. Is it right?
>>
>>
>> 2011/6/24 Jeremy Hunt <[email protected] 
>> <mailto:[email protected]>>
>>
>>
>>     Hi Matt or Vivien,
>>
>>     There is not enough information here, however I did notice:
>>
>>     1. REALM2 would have to be defined with its servers in your 
>> configuration files on the machine you are running kadmin on. This is so the 
>> kadmin program knows which remote system the kadmin daemon is running on and 
>> so can attempt a connection.
>>     2. If the configuration files are correct then the kadmin logs on the 
>> remote system may have some useful information. Your local machine would not 
>> be expected to log errors from a remote machine.
>>     3. I am assuming admin/fqdn1 is the administration principal in REALM1. 
>> On the remote system I would expect the administration principal for REALM2 
>> to be admin/fqdn2.
>>     4. If the entry for admin/fqdn2 is not in the keytab admin.fqdn1, then 
>> copy the keytab admin.fqdn2 to your local system.
>>     5. If there is a authentication failure, you might find an error in the 
>> kdc logs rather than the kadmin logs.
>>
>>     So:
>>     1. Check your configuration files are set up properly, you have to 
>> define both realms in them.
>>     2. Check the kdc logs and the kadmin logs on your local and your remote 
>> masters.
>>     3. Make sure you have the correct keytab files and entries.
>>     4. Try this command after your configuration files and keytabs are 
>> correct:
>>
>>     kadmin -kt /etc/keytabs/admin.fqdn2.keytab -p admin/fqdn2 -r REALM2
>>
>>     Good Luck,
>>
>>     Jeremy
>>
>>      V wrote:
>>
>>         Hello,
>>
>>         we are running kerberos v1.8.1 and trying to run kadmin from REALM1 
>> to
>>         REALM2 by:
>>
>>         *kadmin -kt /etc/keytabs/admin.fqdn1.keytab -p admin/fqdn1 -r REALM2*
>>
>>         but it doesn't work. The message in the console is:
>>         *
>>         kadmin: GSS-API (or Kerberos) error while initializing kadmin 
>> interface*
>>
>>         and there is no error in the kdc/kadmin log.
>>         If we change "-r REALM2" by "-r REALM1", it works and we can 
>> administrate
>>         local kdc.
>>
>>         Can you help us please?
>>
>>         Thank you,
>>
>>         Matt
>>         ________________________________________________
>>         Kerberos mailing list [email protected] <mailto:[email protected]>
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>>
>>
>>
>

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