One of the most important systems for web hosting is the domain name system (DNS), a network component that translates domain names to machine-readable internet protocol (IP) addresses. If the DNS stops working, your website becomes unavailable to most visitors. Despite the DNS being so critical, most people don’t understand what it is or how it works. In this article, you’ll learn the basics of DNS and how it can impact your website.
- What DNS is
- How DNS impacts web hosting
- Potential DNS issues
What Is DNS in Web Hosting?
Most people have heard of IP addresses — a series of numbers that make each device or destination on the internet unique. An IP address looks something like 192.168.0.1, the format used for version 4 of IP (IPv4). While there are more than 4 billion possible addresses in IPv4, the number of websites and devices is still expanding so quickly that IPv6 is becoming the standard.
An IPv6 address looks something like this: 2001:0db8:85a3:2b73:0370:8a2e:0331:0adB. The new format uses eight segments of four alphanumeric digits, which technically allows for 340 undecillion addresses, although not all of them are currently available and likely never will be.
How DNS works
Most people don’t want to memorize the IP address (either IPv4 or IPv6) of every website they want to visit. The DNS technology takes the domain name you’re familiar with, Digital.com, for example, and determines its IP address from a large database.
Without DNS, you would type the IP of a website manually to access it, which would be difficult and inconvenient. While DNS runs behind the scenes, it impacts your website in many ways it is important to be aware of.
How Does DNS Impact Your Web Hosting?
In normal situations, the way DNS impacts your website most is by telling computer systems trying to access it where it is. If you have never been to Digital.com and typed it into your browser’s address bar, it first sends a message to the DNS platform nearest to you. The DNS platform takes several steps to determine where Digital.com is hosted and lets your computer know.
Your computer then requests the Digital.com hosting server and begins communicating normally. It also saves a record locally on your computer so that, in the future, it doesn’t need to check the DNS servers to load the page. But that record needs to be updated occasionally.
While DNS is one technology, it’s spread out over many different servers and locations so it’s very resilient. Some potential issues your website could experience due to challenges with DNS include the following:
- DNS is down: If all of the DNS servers in a region are down, nobody from that area can access your site unless they have visited it in the past and still have an active DNS record saved. This is quite rare since there are many layers of redundancy built into DNS.
- Slow DNS response times: More common, although still rare, is slowness in the DNS system. Normally DNS responds within tiny fractions of a second, so you don’t even realize it is happening. If the server that a potential visitor is having issues; however, it may take several seconds to reply, making it appear as if your site is slow to respond.
- Outdated DNS records: If you move your site to a new hosting company but don’t update DNS through nameservers (see below), the DNS continues to direct traffic to the old location, which may no longer be active.
Of these three possible issues, the third is the most common and avoidable since it’s directly controlled by the website owner.
DNS and nameservers
One of the most important parts of the domain name system is the nameservers. In addition, they’re the components you can configure, at least in part. When you buy a domain, you’ll be given the option to update what nameservers are used for your website. These are always found with the company you used to register the domain, which may or may not be the company you’re hosting the site with.
For example, GoDaddy, a popular domain name registration company, also offers web hosting services. But many people register their domain with GoDaddy and then figure out which hosting company is best based on their needs. If you register with GoDaddy and have your site hosted with Bluehost, you must update your nameservers on GoDaddy by logging on to your GoDaddy account and editing the name servers to be “ns1.bluehost.com” and “ns2.bluehost.com.”
While you can have more than two nameservers, almost all hosting companies only provide two. Once you have them updated, this information is propagated out through all of the DNS platforms, so they all know where to send traffic trying to reach your site.
Understanding DNS A records
Another important thing to be aware of is DNS address records, typically called “A records,” which are used to map various subdomains and other aspects of your site to the appropriate places. While there’s plenty to learn about A records, the main points are to at least be aware of include the following:
- Type: There are many types of A records, each used to control something different. For example, an “MX record” is for a mail exchanger, which controls which email servers are used.
- Host: The host field, or name field, indicates where the specific record’s information is hosted.
- Value: The value is the IP address of the system that the A record provides information about.
- Time to live (TTL): This is a timeout configuration. If you set the TTL to 12 hours, for example, a site that accesses that record won’t check for updates for 12 hours. If you make changes to your A record, anyone who accessed it within the 12 hours before the change will still be using outdated information, so keeping the TTL to a shorter length is often smart.
Fortunately, most A records can be left to their default values unless you have a specific reason for changing them. If you believe you need to change anything related to your DNS other than the name servers on your domain name registration account, you can always reach out to the support team at your hosting company.
Only make DNS changes if you have experience
DNS is an important part of the technologies used to run websites. People who configure and manage DNS for a living typically spend countless hours studying it and becoming certified to have their positions.
If you attempt to make changes to DNS without understanding the potential consequences, it could take your website completely offline or not allow you to access your systems and change things back. You would have to get your hosting company to fix it. It’s smart for any website owner or manager to have a good base-level understanding of DNS. Also, it’s important to avoid unnecessary changes that could cause many problems.