What is DNS?
IP addresses are numerical. They are often long and hard to remember. DNS – the Domain Name System – is the protocol that gives names to the devices that use IP addresses. For instance, “ipv4.global” is the DNS name of IPv4.Global’s website. The DNS tells us that it is hosted at 23.185.0.4.
- Forward DNS maps a name to an IP address
- Reverse DNS maps an IP address to a name
- An authoritative server is the DNS server that gives authoritative answer for a domain name, like ipv4.global
- A DNS resolver is a server that researches answers for users and often caches them, so the research can be reused by other users
The DNS also tells us – with another query – the IP addresses of the mail server for the domain.
It also contains other information, like when to check for a new DNS answer. That lets the machines that get DNS answers store the answers in caches. They can then give them out immediately when asked by other devices. These DNS caches speed up the process for everyone. About 90 percent of DNS answers come from local caches.
Another type of query, reverse DNS, provides a name from an IP address. Mail servers rely on this when deciding whether to accept mail from another machine.
Explore More Related to DNS:
- Blocklists and Reputation
- Addressing Modes, Anycast