Once you purchase a new domain, you need to set up DNS records for it. With those records in place, you will be able to use email hosting and any other services you might have on this domain. A DNS hosting provider for your domain stores your DNS records.
While a DNS hosting service is commonly provided by a domain name registrar, it may also be a dedicated hosting company.
To find out who is responsible for DNS hosting of a domain, you need to find the authoritative DNS servers (or Name Servers) for that domain. A list of DNS servers authoritative for the domain is shown in the Name Server (NS) record. To find this record, you can use the NSLOOKUP tool. Read the Knowledge Base article on How do I use the NSLOOKUP tool provided with Windows? for more information. You can also use Who.is or MxToolbox, or any other website which provides the same functionality.
If you use MxToolbox, you may find your Name Servers using Whois Lookup: select Whois Lookup and type your domain here > click the button to proceed.
Check Name Servers for you domain.
In this example, Name Servers are NS*.DOMAINCONTROL.COM. These Name Servers belong to GoDaddy. Here you may see a list of most common Name Servers and the DNS hosting companies that own them.
MxToolbox also allows to find your DNS host the easier way: locate A record box and type your domain name here > click the button to proceed.
You will see who your DNS hosting provider is.
Sometimes you may also see the company that IP address belongs to, and in some cases it matches your DNS hosting provider name.
However, sometimes they are different.
If your DNS host is Smarsh Hosted Services, you may also check this article: What is the YOUR COMPANY Name Servers (DNS) information?