It can be useful to find the main DNS servers for a domain name and see if you can query it directly to ensure the value you got from your DNS server is the most recent. For this, you can simply use nslookup tools, which is available by default on either most Unix distributions and also on Windows.
~$ nslookup > set querytype=soa > python.org Server: 8.8.8.8 Address: 8.8.8.8#53 Non-authoritative answer: python.org origin = ns1.p11.dynect.net mail addr = infrastructure-staff.python.org serial = 2014110501 refresh = 3600 retry = 600 expire = 604800 minimum = 3600 Authoritative answers can be found from: python.org nameserver = ns2.p11.dynect.net. python.org nameserver = ns4.p11.dynect.net. python.org nameserver = ns1.p11.dynect.net. python.org nameserver = ns3.p11.dynect.net. ns1.p11.dynect.net internet address = 208.78.70.11 ns2.p11.dynect.net internet address = 204.13.250.11 ns3.p11.dynect.net internet address = 208.78.71.11 ns4.p11.dynect.net internet address = 204.13.251.11
Here you can see you got the main NS servers for the domain name “python.org” with the IP addresses associated for each NS.