How do I find the authoritative name-server for a domain name?

Question

How can I find the origins of conflicting DNS records?

Answer 1

You used the singular in your question but there are typically several authoritative name servers, the RFC 1034 recommends at least two.

Unless you mean "primary name server" and not "authoritative name server". The secondary name servers are authoritative.

To find out the name servers of a domain on Unix:

  % dig +short NS stackoverflow.com
 ns52.domaincontrol.com.
 ns51.domaincontrol.com.

To find out the server listed as primary (the notion of "primary" is quite fuzzy these days and typically has no good answer):

% dig +short  SOA stackoverflow.com | cut -d' ' -f1
ns51.domaincontrol.com.

To check discrepencies between name servers, my preference goes to the old check_soa tool, described in Liu & Albitz "DNS & BIND" book (O'Reilly editor). The source code is available in http://examples.oreilly.com/dns5/

% check_soa stackoverflow.com
ns51.domaincontrol.com has serial number 2008041300
ns52.domaincontrol.com has serial number 2008041300

Here, the two authoritative name servers have the same serial number. Good.