RE: [xymon] Can we verify the DNS response

["Mike Cavanagh" <mike (at) terrapintesting.com>]

Richand and Vernon.  Thanks for the replies.

 

Richard, I will look into the concept of a "fake" host entry.  It sounds
like a good workaround.  I am not sure what the testip is for but I will
look into it.  For that matter, not sure if I still need the network
option (comes from BB).  I think I can remove it.  Do not seem to see it
in the Xymon docs.

 

The entries I presented earlier were not real.  I wanted to keep it
simple to help understand what I was trying to accomplish.  Here is what
I am running on (items changed to protect the innocent).  It seems to be
running correctly, but Xymon has been running for just 2 days so I am
still learning its ins n outs.

 

BB-Hosts file:

192.168.14.15          bambam.domain.com           # conn network
prtdiag ftp smtp dns=smtp.domain.com

76.x.y.z                  ns1.domain.com                 # noconn
dns=smtp.domain.com

 

 

Here are the results from Xymon DNS queries:

For bambam.domain.com

            Service dns on bambam.domain.com is OK (up)
            id: 60029
            flags: qr aa rd ra 
            opcode: QUERY
            rcode: NOERROR
            Questions:
                        smtp.domain.com .
A
            Answers:
                        smtp.domain.com .            86400    A
192.168.11.15
            NS records:
                        domain.com      .              86400    NS
ns1.domain.com.
                        domain.com      .              86400    NS
ns1.domain2.com.
            Additional records:
                        ns1.domain.com  .            86400    A
192.168.14.15
                        ns1.domain2.com.             86400    A
192.168.11.15
            Seconds: 0.098

For ns1.domain.com

        Service dns on ns1.domain.com is OK (up)
        id: 2822
        flags: qr aa rd 
        opcode: QUERY
        rcode: NOERROR
        Questions:
                smtp.domain.com .              A
        Answers:
                smtp.domain.com .      86400   A       71.a.b.d
        NS records:
                domain.com      .      86400   NS      ns1.domain2.com.
                domain.com      .      86400   NS      ns1.domain.com.
        Additional records:
                ns1.domain.com  .      86400   A       76.x.y.z
                ns1.domain2.com.       86400   A       71.a.b.c
        Seconds: 0.099
 

Please drop a note if you see something that is just does not seem
correct.

Thanks,
Mike
 
 
________________________________


From: Vernon Everett [mailto:everett.vernon (at) gmail.com] 
Sent: Wednesday, November 03, 2010 7:01 PM
To: xymon (at) xymon.com
Subject: Re: [xymon] Can we verify the DNS response

 

Hi Mike

As Richard suggests, I suspect the config you proposed is going to cause
Xymon, and yourself a world of hurt.
Remember, Xymon uses the hostname as the index (for lack of a better
word)
Now you have the same host with 2 IP addresses.
Xymon will perform 2 pings, using lookup to resolve IP. bbtest-net is
going to bleat.
I suspect, the IP address from the lookup is the one that will be used
as the DNS server IP.
So both DNS lookups will be to the same IP address.

I would suggest a simple script to do what you need.

Regards
     Vernon



On Thu, Nov 4, 2010 at 8:21 AM, Mike Cavanagh <mike (at) terrapintesting.com>
wrote:

An entry in the bb-host file like:

 

192.168.10.10     bambam              # dns=fred

 

will perform a DNS query against the server bambam for the hostname:
fred.  The way I understand it is if a response is received, the DNS is
considered good.

 

I would like to know if here are any options to verify the result.  In
my particular case, we want to query against a "Split DNS" server and
confirm the correct IP is being returned in the A record.  So,

 

192.168.10.10     bambam.dom.com                         #
dns=fred.dom.com

71.137.200.10     bambam.dom.com                         #
dns=fred.dom.com

 

The first entry should return:  192.168.10.15

The second entry should return: 71.137.200.15

 

If DNS views are broken, the 2nd entry may return:  192.168.10.15   If
so, I want to get a page so DNS can be fixed.

 

Thanks,

Mike