Yes, that is the Fully qualified domain name (FQDN) of the DNS servers for domain name resolution. ns1 is a standard naming scheme (name server 1), though don't necessarily always want to point it out, HELLO THIS IS A NAME SERVER for security reasons, but for a lab and teaching purposes, suits the bill.
On the ns1.mydomain.name and ns2.mydomain.name, you probably have MS' DNS server installed as a role and running.
Comments
On the ns1.mydomain.name and ns2.mydomain.name, you probably have MS' DNS server installed as a role and running.