How reverse DNS works
Reverse names live under in-addr.arpa (IPv4) and ip6.arpa (IPv6). For 192.0.2.25 the resolver asks for the PTR record of 25.2.0.192.in-addr.arpa. Whoever holds the address block controls those records, usually the provider or hosting company, not the domain owner.
Forward-confirmed reverse DNS
A PTR record alone can name anything. Forward-confirmed means the name it gives also has an A or AAAA record leading back to the same address. Receiving mail servers check this; set it through your hosting provider's control panel.
Questions
- My home address has no reverse DNS. Is that a problem?
- No. It only matters for servers, mostly mail servers.