What is DNS Software?
DNS software is a program that is installed on a web server and used to facilitate the transference of data related to the domain name system. Technically, any web server can have DNS software installed on it, making the server a name server; however, some web hosts will not allow you to install or configure software within your hosting control panel, especially in shared hosting plans.
If you’re interested in installing DNS software on a web server to create a custom nameserver, you'll either need a VPS or dedicated hosting plan, unless you'd like to invest several thousand dollars in a private web server.
What is a Name Server?
A name server is a web server that has DNS software installed on it, particularly a server that is managed by a web host that is specifically designated for managing the domain names that are associated with all of the hosting provider's accounts.
Name servers are often called DSN servers as well, and this is likely the origin of all of the confusion associated with name servers and the DNS.
Every website has two name servers to which it is pointed, and this process must be done by the webmaster upon purchasing a domain and a hosting account.