I need to check a reverse dns using the DNS servers of some domains. But I'm having some problems.
dig -x 212.26.146.21 +short
mx20.gypost.com.
all ok
dig -x 212.26.146.21 @8.8.8.8 +short
mx20.gypost.com.
its ok too
dig SOA google.com +short
ns1.google.com. dns-admin.google.com. 2014021800 7200 1800 1209600 300
dig -x 212.26.146.21 @ns1.google.com +short
empty
I can't find reverse address using NS record of any domain. What i do wrong? And how i can check my reverse address using dns server of gmx.com, for example.