The Simplest and Most Effective Way to Combat Spam

DNS Basics

All computers on the internet, from smartphones and laptops to servers serving content for massive retail websites, use numbers to find and communicate with each other. These numbers are called IP addresses. When you open a web browser to visit a website, you don't need to remember and enter these long numbers; instead, you enter a domain name like example.com to connect to the correct location.

DNS services like Amazon Route 53 are globally distributed services that translate human-readable names like www.example.com into numeric IP addresses like 192.0.2.1, which computers use to connect to each other. The internet's DNS system works similarly to a phone book, managing the mapping between names and numbers. DNS servers translate name requests into IP addresses, controlling which server an end user connects to when they enter a domain name into a web browser. These requests are called queries.

Types of DNS Services

Authoritative DNS Service: An authoritative DNS service provides an update mechanism for developers to manage their public DNS names. It then responds to DNS queries by translating domain names into IP addresses so that computers can communicate. Authoritative DNS has the final authority over a domain and is responsible for providing IP address information to recursive DNS servers. Amazon Route 53 is an authoritative DNS system.

Recursive DNS: Clients typically do not issue queries directly to authoritative DNS services but instead connect to another type of DNS service called a resolver, or recursive DNS service. A recursive DNS service acts like a hotel concierge; while it does not own any DNS records, it serves as an intermediary that can retrieve DNS information on your behalf. If the recursive DNS has cached the DNS reference, or has stored it for a period of time, it responds to the DNS query by providing the source or IP information. If not, it passes the query to one or more authoritative DNS servers to find the information.