[Xymon] Modernizing the DNS check

[Adam Goryachev]

On 08/01/14 19:39, Henrik Størner wrote:
> Den 08-01-2014 06:07, Jeremy Laidman skrev:
>> On 8 January 2014 13:44, Mark Felder <feld at feld.me
>> <mailto:feld at feld.me>> wrote:
>>
>>     The question here is "Are the publicly accessible NS servers in a
>>     consistent functional state?". The goal is not to validate the data.
>>
>>
>> So, I suppose the "object" you're trying to watch is the
>> "NS" consistency state of the zone.  So yes, you'd alert against the
>> zone name such as what you've shown in your hosts.cfg example.
>
> Testing this would essentially do
>
>    dig example.com ns
>    <grab the list of dns servers>
>    dig @ns1 example.com soa
>    dig @ns2 example.com soa
>    <compare soa records to see if they are identical>
>
> Xymon can do the DNS lookups, all that is needed is to cook up the
> necessary data analysis.
>
> I think this should be a separate test from the normal "dns" column?
>
IMHO, this really should be an ext test. In a couple of minutes, this 
might almost suffice with some small extra wrappers:
/usr/bin/dnsqr ns mydomain.com|grep ^answer|awk '{ print $5 }'| while 
read server;do /usr/bin/dnsq soa mydomain.com $server|grep ^answer:|awk 
'{ print $7 }';done|uniq|wc -l

If the answer is 1, then green, anything else is red.

Of course, I've only tested this against my own domain on my NS, and it 
worked, but your results may vary. You should add a whole bunch of error 
checking to ensure that each lookup is successful, returns valid 
results, etc...
The main reason for doing this was to simply see how hard it would be to 
complete the task using the djb tools as they are claimed to be easier 
to use for scripting. I didn't actually attempt this with the bind 
tools, but past experience suggests it would be more difficult to parse 
the correct answers/etc...

Sharing was just in case it is useful to others...

Regards,
Adam
-- 
Adam Goryachev Website Managers www.websitemanagers.com.au