Ensuring Business Continuity: The Importance of DNS Reliability

DNS or the Domain Name System is one of the most important network systems in use today. The entire internet relies on the function of the DNS. One of the core functions of DNS is to map domain names to IP addresses.

The domain name is the unique title of a website in the URL. For example, in https://google.com, “Google.com” is the domain name.

Why is there a need to map domain names to IP addresses anyway? It’s not like we use IP addresses, we only use domain names.

The answer is that computers can’t find resources using just the domain name. They can only understand IP addresses. Humans on the other hand cannot remember IP addresses reliably. The DNS solves this problem efficiently.

However, that is just one of many things it does. In this article, we will learn the importance of the DNS system and why it needs to be reliable.

Constituents of DNS

To get a full picture of the importance of DNS we need to understand its constituents and how it works. Let’s start with DNS records.

DNS Records

DNS records are text files stored on DNS servers. They contain important information about various domains. The IP address information is stored on either the A or AAAA records. A record maps IPv4 addresses while AAAA maps IPv6 records.

However, other records like MX (mail exchange), SPF (Sender policy framework), and PTR (pointer) also exist. They perform functions such as:

• Designating which mail server receives email on behalf of a domain (MX)
• Listing out all authorized mail servers that can send email on behalf of a domain (SPF)
• Mapping an IP address to a domain instead of a domain to an IP (PTR).

There are many other DNS records, some of them are responsible for the security of the DNS system, while others fulfill other functions.

Server Levels 

The DNS works on a hierarchical system of servers. There are multiple DNS servers throughout the world that store DNS records of various domains. However, not all servers have the same authority or contain the same information.

The servers in a hierarchy are as follows:

• Root servers
• Top-level domain servers (TLD)
• Authoritative name servers
• Recursive resolvers

The lowest in the hierarchy are resolvers. Their job is to receive DNS requests from client computers and query the other servers recursively to resolve the requests.

DNS Lookup Process

The first server a resolver queries is the root server. The root server only has information on the root part of the domain name. Here is a URL to help you understand the different parts of a domain name.

“google.com.”

The green part which is the dot is called the root domain. The blue part–the .com– is called the TLD. The final pink part is called the domain name. If there was a ‘www’ at the start, that would be the subdomain.

So, root servers have data about the root domain. But they don’t keep all of it there. They only store information about the TLD server that has the real data. So, if a domain name exists and the root server knows about it, it will send the resolver to the TLD server that has more information about it.

The TLD server also only stores information about the authoritative nameservers that have the actual data about the domain. So they send the resolver to them. The nameservers provide the complete information required to resolve the request.

This process in which the resolver queries each server in the hierarchy is known as the DNS lookup process. The information that the resolver is seeking is DNS records.

All of the servers in the hierarchy have multiple copies to provide redundancy. This improves the reliability of the DNS system. In the case a DNS server fails, the copies can still perform their function and the system keeps on running.

What Does it Mean For Businesses if DNS is Unreliable? 

All online businesses are extremely reliant on the domain name system. An e-commerce website relies on the DNS. If the DNS system is not functioning well, or the records of the domain are not maintained correctly it can have several consequences.

Some of the most dire consequences of dysfunctional DNS are given below.

1. E-commerce Portal Won’t Be Reachable

If the DNS system is not working, then the most obvious outcome is that the website of an online business will be unreachable. The most common reason for this to occur is that the A and AAAA records are incorrect, or the DNS server in charge of storing them is having some trouble.

If your customers cannot find your store, then they cannot do business with you. So your business will face financial loss.

2. Slow Performance

An unreliable DNS setup results in longer request resolution. In a good setup, there are CDNs or content delivery networks that are situated closer to clients. These hold a lot of DNS records in their cache. This means they don’t have to do the full DNS lookup process. As a result, the site loads faster.

However, if your DNS records are not maintained well, the CDNs have to constantly retrieve the latest version of the records by doing the full lookup, and that adds to the loading time.

3. Security Concerns 

If your business is not using the latest security protocols for securing your DNS, then it can result in hacking incidents. DNSSEC is one of the most useful protocols for securing DNS. It ensures that DNS records are not intercepted and altered maliciously.

However, if you are using an older version of DNS to save money or something, you will find that DNSSEC doesn’t work on them. This means that your records can be altered to redirect visitors to other malicious websites without your knowledge.

This results in a hit to reputation and loss of businesses.

4. Communication Disruption

If your MX, SPF, and DKIM records are not maintained well, then your customers’ and business partners’ emails will not be able to reach you. Emails are by far the most important medium of communication in the business world.

A communication disruption of this medium means that your business deals may fall through and your customers will be disappointed. So, it is important to secure reliable DNS to avoid these outcomes.

How Can Businesses Make DNS More Reliable?

The actual infrastructure of DNS is very reliable. As we mentioned earlier, each server in the DNS hierarchy has multiple copies for redundancy. So the unreliability in the system is introduced from the domain admin’s side.

Domain admins are responsible for creating and managing their domain’s records. So, businesses can make their end of the DNS system by implementing best practices such as the following.

• Implement redundancy for DNS servers in your intranet
• Configure an access control list (ACL) for all DNS servers.
• Hide sensitive DNS records
• Enable DNSSEC
• If your business has multiple offices around the world, implement a local DNS for every location
• Use DNS Lookup tools and propagation checkers to keep an eye on your DNS record status.

If you can implement all of these practices, your DNS will become more reliable and ensure business continuity.

Conclusion 

DNS is the backbone of the internet. Businesses rely on it heavily. As such, it needs to be extremely resilient. Public DNS infrastructure is very reliable already, so the onus is on the businesses to beef up their private DNS systems.