How does DNS work? Types and operating modes
As part of the anatomy of a URL, as we explained here, there are one important item with lot’s of ramifications: the Domain Name.
The Domain Name in a URL is part of DNS (Domain Name System) which is a name management system for network connected resources. It basically translates human-readable domain names into numerical IP Addresses needed for the purpose of locating and identifying clients and servers throughout a network.
DNS allows data to be stored in the entry, allowing different types of records to be created, all with different purposes, let’s go through them:
The A record maps a name to one or more IP addresses, when the IP are known and stable,
ex: viewlike.us. IN A 126.96.36.199
Maps a IPv6 address record to a hostname
ex: www IN AAAA 2001:db8::3
Makes one domain name an alias of another. The aliased domain gets all the subdomains and DNS records of the original. Ideal if you want to associate a subdomain to an already existing A record.
ex: www.viewlike.us to viewlike.us – knowing that “viewlike.us” has a A record pointing to the server IP.
An email-associated record, maps a domain name to the email server for that domain.
ex: viewlike.us. 300 IN MX 10 viewlike.us.
The record says all emails going to @viewlike.us should go to the IP behind the record viewlike.us with priority 10.
Implements a IPv4 Reverse Lookup for the IP address of the domain and it’s basically the opposite of a A record. One maps a name to a IP and the other a IP to a name. When you have the PTR record setup, you can get the associated domain/hostname. An A record should exist for every PTR record.
Ex: if an A Record points viewlike.us to 188.8.131.52, a PTR record would look like:
184.108.40.206.in-addr.arpa. 3600 IN PTR viewlike.us.
Allows an administrator to add text to the DNS record, and it’s commonly used to implement a SPF (Sender policy framework) as a method to fight spam. In the TXT record, we can declare a list of authorized hostnames and IP’s from where email can originate from.
Ex: v=spf1 a mx ip4:220.127.116.11 -all
Use a DNS service provider
Services like Cloudflare make all of this easier: Clean and easy interface plenty of helpful resources, improvements in the website performance, caching, security and it’s free.
You’ll see it’s much easier to manage your DNS settings using a service like this – you can tank me later.