[Xymon] DNS test interaction with 0.0.0.0

[John Thurston]

On 4/5/2016 5:50 PM, J.C. Cleaver wrote:
- snip -
> It might be because DNS is tested distinct from the resolution involved in
> initial xymonnet setup.

I think it is more than that. Please consider this test condition:
> 10.10.10.10 	ns1-int.foo.com 	# noconn dns=ns1.foo.com
> 0.0.0.0 	ns2-int.foo.com 	# noconn dns=ns2.foo.com
> 0.0.0.0 	ns3-int.foo.com 	# noconn dns

In this case, snooping the network while explicitly running xymonnet 
shows very different results for ns2-int and ns3-int

When testing ns2-int, there is a query to the normal resolver asking for 
an address for ns2-int.foo.com and there is an answer. That is all.

When testing ns3-int, the query to the normal resolver for 
ns3-int.foo.com is performed (and answered). This if followed by a query 
to ns3-int.foo.com for ns3-int.foo.com.

The presence of the equal-sign separated parameter to the DNS test is 
breaking the test function. In my tests, the equal-sign syntax is only 
functional if the host to be tested is specified with an ip address. 
This is true even if xymonnet is called with --dns=only

I suspect xymonnet is finding the equal-sign, but not parsing the 
parameters and adding them to the query list. The dns-test code, is then 
being asked to perform a lookup for nothing, and is doing exactly that. 
The non-results are then evaluated, no success-markers are found, so the 
test is reported as RED.

These tests have been performed on Solaris 10 with 4.3.26. I'm going to 
try similar tests on Linux on 4.3.17 and see how those results compare.

-- 
    Do things because you should, not just because you can.

John Thurston    907-465-8591
John.Thurston at alaska.gov
Enterprise Technology Services
Department of Administration
State of Alaska