Domain Name System

A Domain Name System (DNS) translates a domain name such as www.example.com to an IP address.

DNS is hierarchical, with a few authoritative servers at the top level. Your router or ISP provides information about which DNS server(s) to contact when doing a lookup. Lower level DNS servers cache mappings, which could become stale due to DNS propagation delays. DNS results can also be cached by your browser or OS for a certain period of time, determined by the time to live (TTL).

• NS record (name server) - Specifies the DNS servers for your domain/subdomain.
• MX record (mail exchange) - Specifies the mail servers for accepting messages.
• A record (address) - Points a name to an IP address.
• CNAME (canonical) - Points a name to another name or CNAME (example.com to www.example.com) or to an A record.

Services such as CloudFlare and Route53 provide managed DNS services. Some DNS services can route traffic through various methods:

*   Prevent traffic from going to servers under maintenance
*   Balance between varying cluster sizes
*   A/B testing

Visit the following resources to learn more:

• @opensource@Getting started with Domain Name System
• @article@What is DNS?
• @article@Latency Based
• @article@Geolocation Based
• @article@Weighted Round Robin