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Reverse DNS lookup check not working

list Jeremy Laidman
Mon, 8 Apr 2013 00:34:26 +1000
Message-Id: <CAAnki7C4-m8p=PkEs1uti05n62u3dv0y=user-e14cc3b2834e@xymon.invalid>

On 5 April 2013 22:30, SebA <user-4631430d620a@xymon.invalid> wrote:
**
I wonder if it could be related to the fact that DiG needs to be invoked
with -x for PTR checks.
Not required for PTR checks.

  A quick look at the DiG man page suggests you could use either:
# dig -t PTR my.ip.ad.dr.ess
Or:
 # dig my.ip.ad.dr.ess PTR
No, it's more like this:

# dig ess.addr.ip.my.in-addr.arpa PTR

However, this is not the case.  A closer looks reveals you have to use:
 # dig -x my.ip.ad.dr.ess
The -x option is a convenience, and it means not only "set type to PTR" but
also "reverse octets and append 'in-addr.arpa'".

I'm not in a position to check until tomorrow, but I'm confident that I
successfully test for the localhost address like so

  DNS=PTR:1.0.0.127.in-addr.arpa

J