Fast, Powerful, and Secure DNS

What Is DNS?

While meaningful to a computer, IP addresses (like this one, “2a06:98c0::/29”), are nigh-unintelligible to human beings. Even if you’re in the select group of people who understand these complex strings of numbers, letters, dots, and slashes, memorizing multiple addresses would be a slow and painful process. Furthermore, if the address and name of a website were fixed together, then changing the location of a web resource would be a rather cumbersome and difficult process because the name would also fundamentally change each the time website was moved. Thankfully, DNS, or Domain Name System, is a relatively painless way of using easily remembered URLs (or Universal Resource Locator) to navigate to web resources.

DNS is a fundamental feature of the internet that allows web resources to be systematically found and used by anyone online. If you imagine the internet to be a physical network of streets and roads lined with web properties, then you can think of DNS as an address book containing the IP addresses of specific web resources. A typical DNS lookup can be thought of like this: when someone types the URL of a website they’re trying to access into their browser, their browser uses DNS to lookup the URL and find its corresponding IP address. With this IP address the browser then navigates to the desired site, all without any interaction from the user. In short, DNS is the system through which human-understood domain names get translated into computable IP addresses.

How Does DNS Work?

Because the Internet is constantly changing, it’s incredibly difficult to maintain an up-to-date directory of every web resource name and its respective location. DNS has evolved into two distinct and necessary types: recursive and authoritative nameservers. Recursive DNS nameservers don’t contain IP addresses for domains, but rather function to recursively search through possible locations where those addresses are stored. By leveraging recursive searches for the locations of web properties through DNS, the internet can be as rapidly changing and dynamic as possible— new answers to recursive calls can be easily added without changing how the recursive search works.

The other type of DNS, Authoritative DNS nameservers, store the actual records of IP addresses for respective domains. When a recursive DNS server searches through DNS records, it searches records stored on Authoritative DNS nameservers.

The first place that is searched in a DNS query is the DNS root server. There are 13 DNS root servers around the world run by 12 independent organizations. DNS root servers function to provide the location of the authoritative server of every TLD, or top level domain (.com, .edu, .net, etc.). After the location of the authoritative server for the TLD has been found, that server is used to find the location for the authoritative server for the domain itself, which will return the address of the desired domain.

Benefits of Managed, Anycast DNS

There are two potential issues with the DNS model described above. First, if you’re using a single authoritative nameserver to store the DNS records for your web property, then there can be dramatic latency for those accessing that server due to geographic distance. That is, if your server is located in the United States, and someone in Australia is trying to access your web property there can be a noticeable delay for them before any content is even loaded. Second, if your authoritative nameserver goes offline, then your web property can become entirely inaccessible, even if the property itself is still online.

To solve this issues, Cloudflare provides a managed Anycast DNS service. Cloudflare works to make its Anycast DNS service as fast and reliable as possible. By serving records from over 102 points of presence (PoP’s) around the world customers can see dramatic latency and reliability improvements. Anycast technology allows Cloudflare’s DNS to serve the same records from multiple locations and to route DNS inquiries to the nearest point of presence in order to ensure the lowest latency possible. Therefore, a site using Cloudflare’s DNS serves records from the same region as the originating request. While Anycast technology ensures that your DNS records are being served as fast as possible, it also provides redundancies that prevent offline servers from stopping the flow of traffic to your site. For example, if there is a network issue in Barcelona, then traffic is automatically routed through Madrid, which ensures your DNS records are continuously served without interruption.