View selection via TSIG

Josh Paetzel josh at tcbug.org
Tue Aug 18 05:32:54 UTC 2009


On Aug 17, 2009, at 11:08 PM, Mark Andrews wrote:

>
> In message <96123FB1-1F2E-493C-BBB8-24A86A1DD99A at tcbug.org>, Josh  
> Paetzel write
> s:
>>
>> On Aug 16, 2009, at 12:26 AM, Mark Andrews wrote:
>>
>>>
>>> In message <5EA10B89-4650-4F82-A41D-CB511CE2A9A9 at tcbug.org>, Josh
>>> Paetzel write
>>> s:
>>>> I've googled a bit and been unable to find the solution that I  
>>>> need.
>>>>
>>>> I have a master nameserver that has 4 views configured.  I have a
>>>> slave for this that is currently using 4 IPs to slave the views.
>>>> This
>>>> works fairly well, except that the slave server is unable to handle
>>>> NOTIFY from the master.  So when I do an update to a zone I have to
>>>> stop the slave, delete it's cache files, and restart it.  The slave
>>>> is
>>>> able to properly load zones, since it uses the correct IPs to
>>>> transfer
>>>> the zones, and it gets the right views, all is well.
>>>>
>>>> I've read that BIND 9.3 can use TSIG for view selection, but all  
>>>> I've
>>>> ben able to find is using TSIG for one view, and no TSIG for the
>>>> other
>>>> view.  What I would like to do is configure four separate TSIG keys
>>>> and do view selection based on which key is used.
>>>>
>>>> Is this possible?  And where can I find documentation on it?
>>>
>>> 	Yes.  Read the FAQ.
>>>
>>
>> I read the FAQ, and there was a question entitled "How to share a
>> dynamic zone between multiple views?" that seemed to get me most of
>> the way there.  I am now running my slave nameserver on one IP, and
>> zones transfers seem to work fine.  NOTIFY also seems to work for
>> every view but the external view.  This is somewhat perplexing to me.
>> Tomorrow I plan on turning on logging for NOTIFY to see if I can at
>> least determine what is going on.
>>
>> If you have any tips or common gotchas feel free to let me know.
>>
>> Thanks,
>>
>> Josh Paetzel
>
> 	You need to make the notify go to the correct view by using
> 	appropriate server clauses at the view level.  It's a matter
> 	of making what the master sends match what the client expects.
>
> 	Mark
> -- 
> Mark Andrews, ISC
> 1 Seymour St., Dundas Valley, NSW 2117, Australia
> PHONE: +61 2 9871 4742                 INTERNET: marka at isc.org


Well, I found the issue.  If the key is listed last in match-clients  
it works.

// doesn't work
match-clients { key external; all; };

// works
match-clients { all; key external; };

Somehow I think either I've hit a bug, or I'm too tired to fully  
understand how those statements are different, or even more likely,  
that there's something else going on that just makes this work by  
coincidence

It's very reproducible though.  It also only seems to affect my  
external view, all the other views, that match specific  subnets, can  
have the key specified anywhere in the list.

So to reiterate:

Zone transfers worked properly for all views

The slave updated properly upon receiving NOTIFY for every zone but  
the external view.

Any update that resulted in a NOTIFY being set for the external view  
was not picked up by the slave.

The differences between the external view and all the other views was  
the external view was last, it had any in it's match-clients and  
recursion turned off.

Thanks,

Josh Paetzel







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