There are a number of ways to check this, however, we find the most reliable to be a simple ‘whois’ check.
The tool we use most commonly is…
http://whois.domaintools.com/ Or, if you are using a Linux machine…
yum install whois
Then, you can run the following…
whois domain.com
Important: Some people, including many registrars will recommend you find the relevant nameservers of a domain via a DNS lookup, such as whatsmydns.net – this is incorrect.
The NS records that sit within the DNS zone, do **not **always match those sat at the registry of the domain. The only reliable method to find the nameservers being used, is via a WHOIS search.
The reason we recommend the above method, is that this checks directly with the Registrar. DNS Zones are prone to errors, and can, therefore, reflect an incorrect value.