File 149.194.zone

...
10 IN NS ns.company.com.
IN NS ns.provider.net.

The delegation of a domain to functional name servers must be performed by regional Internet registries (RIPE, APNIC, ARIN, AfriNIC, or LACNIC). The hostmaster must request this delegation from the RIPE, APNIC, ARIN, or LACNIC hostmaster using a form. An example is listed in Section 7.1.

The company, Company Ltd., has a branch. This branch uses 128 IP addresses, i.e., the subnetwork 194.149.10.128 194.149.10.255. The branch is administering its own name server with the name ns.branch.company.com and an IP address of 194.149.10.129. Therefore it is convenient that the reverse domain for the subnetwork 194.149.10/25 will be delegated to the name server ns.branch.company.com.

This example is quite common in practice, and we will use it for a demonstration of delegating a reverse domain for a subnetwork. But first a little theory.

The delegation of reverse domains...