Updating dns pointers
A Pointer (PTR) record resolves an IP address to a fully-qualified domain name (FQDN) as an opposite to what A record does. Here is what it looks like when performing external DNS lookup: mail servers and external mail servers (e.g.
Dedicated Web Server or Cloud Server) and the external server does not belong to Intermedia infrastructure, you need to create PTR record because it will help your server pass some security tests when connecting to other mail servers.
When you type into your address bar, DNS does the mapping for you behind the scenes. Just like caching on your Word Press site, DNS cache stores the IP addresses (or locations) you have recently visited locally on your computer.