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DNS Best Practices for Improved Site Security and Performance

DNS best practices can increase the security level for you and your clients, improve performance, and make your administration process easier.

In this guide, we’ll share what these best practices are and talk about some of the tools you can use to improve your DNS management. Depending on your personal case, you can perform these actions on your shared hosting account, VPS, private server, cloud DNS provider, or with your domain registrar. 🌐

The easiest way to modify your DNS is if you are using a cloud-based DNS service. These tools provide an easy-to-use control panel where you can deploy name servers, modify the zone file and the DNS records, and add advanced security features.

We’ll share other DNS management tools as they become relevant to the DNS best practices we’re discussing. πŸ’¬

Let’s get started!

πŸ“š Table of contents:

DNS best practices

Secure connection to your DNS servers πŸ”’

Of all the DNS best practices in this article, we can’t stress this one enough, which is also why it’s first on the list. Ensuring a secure connection is a foundational element of any proper DNS setup and can be implemented fairly easily.

You can use an SSH connection to connect to your servers and add additional protection by using an IP blacklist or IP whitelist. Using the blacklist, you can block specific IP addresses from accessing your server. The IP whitelisting method, on the other hand, makes it so that only specific IP addresses can access your server. This massively reduces the risk of intruders infiltrating your servers.

You should also ensure a safe experience for your site visitors. Implement encryption protocols like DNS over TLS (DoT) or DNS over HTTPS (DoH) to encrypt the traffic between them and the DNS servers. This will help prevent eavesdropping.

Make DNS highly available and redundant πŸ”ƒ

If you are experiencing problems with one or more of your websites, or you are under a DDoS attack, you still want your domain(s) to stay available. For that purpose, you need a resilient network of multiple DNS servers.

Yes, this does mean you’ll have multiple DNS servers with the same purpose, but that is the point. You want to be sure that whatever happens, people will still be able to reach your site.

Managing multiple DNS servers, located in different strategic locations, is one of the best practices you can use. Many DNS service providers offer features aimed at enhancing DNS availability and redundancy.

Geo DNS 🌍

One such feature is Geo DNS, which directs users to different servers based on their geographic location. This is an excellent starting point for implementing a more resilient DNS setup. Geo DNS improves response times and load balancing by resolving DNS queries with the IP address of the server that’s geographically closest to the user or best suited to serve the user’s request.

Anycast routing 🌐

Anycast routing often works hand in hand with Geo DNS. It allows all of your DNS servers to share the same IP address, enabling the DNS queries of your clients to be answered by the closest server. This method enhances the availability and performance of your DNS services by ensuring that if the closest server is down due to maintenance or a DNS attack, the query will simply be routed to the next available Anycast DNS server.

Load balancing 🀸

Similarly, load balancing is crucial for distributing incoming DNS queries across multiple servers to ensure speed, optimal performance, and availability. While anycast routing focuses on geographic distribution, load balancing can be more granular, using criteria such as geolocation, current server performance, or query arrival to direct traffic.

DNS load balancer services complement Geo DNS and anycast routing by allowing you to strategically place your servers in different locations, thereby providing excellent service to your site visitors worldwide. This strategy is also beneficial in mitigating the effects of DDoS attacks, as it distributes the traffic among available servers, reducing the impact of the attack. We’ll cover DDoS protection next.

Add DDoS protection πŸ”°

DDoS attacks have become incredibly common in the last decade. These attacks can render your website unreachable, leading to reputation and financial losses. The last thing you want is for someone to type in your domain address only to find out that your site is down.

Luckily, adding DDoS protection is really easy. There are plenty of cloud services that offer DDoS protection. Such a service should include a smart DNS traffic monitor that analyzes the package flow and identifies threats. When it encounters these threats, it should auto-trigger actions to stop or lower the effects of the DNS attack.

DDoS protection will usually include traffic filtering and traffic redirection, stopping the bad traffic while still permitting the regular traffic of your website visitors.

Use a firewall for your DNS servers πŸ“›

Any server that you use, should be protected by a firewall. The firewall will filter your traffic and protect your devices from malicious attacks.

By using a firewall for your DNS servers, you can restrict access to them. You can stop unauthorized users from trying to exploit any vulnerabilities.

You can also use the information that the firewall software provides to evaluate risks. Many firewall programs have log files. These can reveal patterns in traffic, IP addresses of devices, and any unusual or suspicious activities.

If you want some examples of great firewall software for this purpose, check out PfSense, IPFire, or Smoothwall Express.

IPFire firewall dashboard.

Implement DNSSEC πŸ–±οΈ

Because the DNS is not inherently secure, adding an additional level of protection is a part of DNS best practices. This extra security layer on top of the DNS provides encrypted DNS communication and is called DNSSEC.

It uses pairs of public and private cryptographic keys (long alphanumerical sequences). The private keys sign the DNS data and the public keys verify the signature. The whole process starts from the root domain and creates a chain of trust that goes down the hierarchy of the domain name’s servers.

Implementing DNSSEC is considered a DNS best practice because it protects from man-in-the-middle style attacks.

Imagine a cybercriminal trying to modify any DNS record by performing a DNS cache poisoning. The lack of a valid DNSSEC signature would be detected during the verification process, and that would stop the attack.

To enjoy consistent security, update your DNSSEC keys regularly and keep the private keys secured.

Regular software updates βš™οΈ

Keeping your DNS software up to date will provide you with the latest security patches. These patches can fix previous vulnerabilities and ensure that your servers get the best protection available.

To implement this particular DNS best practice, you can create a schedule for checking and updating your DNS servers. Think about when there is less traffic to your domain, and ensure that updates happen during that time. It’s also considered a good practice to update your servers one by one. By doing so, you ensure that there are no service disruptions should any complications arise during the process.

Hide the master DNS server 🚧

The master DNS server is the most important one because you make all changes to the DNS zone file on it. After that, it shares the DNS records with the Secondary DNS servers. If the master server is down, the cache in the secondary servers can expire and your domain can go offline. Needless to say, you don’t want that to happen.

Protect the master DNS server, and stop unauthorized access by hiding it. You can assign a private IP address to the master server and place it on a separate restricted network segment. This will add additional protection and isolation and keep your server safe.

It will still be able to communicate with the secondary servers, but it will be invisible to the public. The secondary servers will respond to the clients’ queries and the only one communicating with the master server will be you.

Monitor your DNS network πŸ•΅οΈ

A DNS monitoring service can help you detect issues, see patterns in the behavior of your clients, ensure optimal performance, and respond to potential security threats.

Yes, you can manually test your DNS servers with the Ping command, the Dig command, or another CLI software that you have on your device, but a specialized DNS monitor will give you more detailed information and a log file with the history of your traffic.

Additionally, it can also provide real-time alerts. Depending on the monitor service you are using, you can get SMS or email notifications that will inform you about critical events, such as DNS server failures or abnormal traffic patterns. This enables proactive intervention before issues escalate.

It is also good to pay attention to the performance of your DNS servers. By checking the performance metrics, including response times and query rates, you can analyze trends to identify potential capacity issues and plan ahead for scalability.

Google Cloud DNS monitoring metrics page.

Two DNS monitoring services you can consider are Google Cloud DNS monitoring and ClouDNS monitoring service.

Restrict zone transfer β›”

Zone transfers are the mechanism of transferring DNS records between servers. When you modify any record in the master, this information must be propagated to the rest of your DNS servers.

Use Access Control Lists (ACLs) to limit which DNS servers are allowed to initiate zone transfer. This is a whitelist method, in which you can add IP addresses of the permitted DNS servers. This will stop cyber criminals from copying your zone data without your permission.

Additionally, you can enable incremental zone transfers. The incremental zone transfer, in contrast to the full zone transfer, transfers only the changes that happened since the last transfer. This reduces the load on the DNS network and improves efficiency.

Audit your zone file πŸ”Ž

Last on our list of DNS best practices is auditing your zone file. Since most of the focus is on DNS traffic and monitoring incoming threats, DNS administrators often neglect the zone file. However, regular audits can be vital for maintaining the accuracy and integrity of your DNS records.

You can create a review schedule to conduct these audits. While performing an audit, you can identify outdated or incorrect DNS records and remove any entries that are no longer valid or necessary to keep your zone file organized.

If your zone file is large, you can assign responsibility to different members of your team. These people can check a particular record type, subdomain, or group of DNS records.

Conclusion 🧐

As you can see, there are many DNS best practices that can ensure the security of your servers.

You should start by limiting access to your servers and keeping them secure with tools like firewalls, DDoS protection, and DNSSEC. You should also monitor the traffic and regularly check your DNS records.

Implementing these DNS best practices will help you provide consistent, fast service to your website visitors.

Want to learn more about DNS management? Check out our guide to fixing the “DNS resolution has high latency problem” to improve your site loading times.