What Is DDNS (Dynamic DNS) and How Does It Work?

Every device that connects to the Internet has an IP address. While the domain name system, or DNS, translates domain names into their corresponding IP addresses, dynamic DNS is responsible for automatically updating DNS records when an IP address changes. In this article, learn what dynamic DNS is, how DDNS works, and its practical applications.

What is DDNS?

DDNS stands for dynamic domain name system. DDNS is a service that automatically updates DNS records every time your IP address changes, which varies depending on whether your IP address is static or dynamic. Dynamic DNS is essentially understood as an extension of DNS.

At the beginning of the Internet, when domain databases were smaller, they could be handled manually. However, tracking IPs now needs to be automated as they change so frequently. This is the role of DDNS; it addresses the issue of frequent changes by updating A and AAAA records when a host changes its IP address.

It benefits both users and hosts; users have access to the most up-to-date information, and network administrators don't need to configure settings for each IP address change. DDNS checks for updated IP addresses on websites, servers, and applications, making it extremely useful in ensuring the accuracy of the DNS database.

What does dynamic DNS do?

Dynamic DNS allows you to access your Internet devices from the Internet even if your IP address changes. While static IP addresses work well with DNS, dynamic IP addresses use DDNS as they frequently change.

Dynamic Host Configuration Protocol (DHCP) assigns dynamic IP addresses, and your Internet service provider lets you use each dynamic IP temporarily. When the IP changes, as it does periodically, DDNS automatically updates your hostname with the correct IP address. This ensures that your hostname stays the same and that you won't lose your connection.

How does dynamic DNS work?

Dynamic DNS operates through a DNS client and a DNS provider. The client, installed on the user's device, monitors and detects changes in the IP address. The agent then periodically communicates these updates to the provider.

The provider manages the DNS zone for the registered domain and dynamically updates the associated IP address whenever changes occur.

Next, DNS propagation ensures that the updated information is distributed across the Internet, making the domain accessible via the new IP address. By updating the DNS records automatically, DDNS eliminates the need for human intervention and automatically ensures that your domain name always points to the correct IP address.

Types of DDNS

There are two main types of dynamic DNS available: standards-based DDNS and proprietary DDNS.

Standards-based DDNS

The standards-based DDNS is sometimes referred to as dynamic DNS update. It uses an extension of the DNS protocol to request an update. It offers a reliable and secure way to keep DNS records updated. Because of this, many companies use it to register their addresses for company computers.

This DDNS extension is defined in RFC 2136, which is a standard published by the Internet Engineering Task Force (IETF).

Standards-based DDNS providers offer features such as automatic IP updates, two-factor authentication and IP address verification as security measures, and the ability to scale to meet the needs of all companies, regardless of size.

Proprietary DDNS

Proprietary DNS uses custom implementations. This type of DDNS is a good choice for home networks and small businesses. Though it isn't as widely supported as standards-based, it's more flexible and easier to use.

Proprietary DDNS providers offer support for custom domains, easy integration with popular home networking devices, and simple web-based management interface.

Benefits of dynamic DNS

Dynamic DNS enables you to access network resources easily, making it useful for home users and organizations that need to access online servers and websites from remote locations. Other benefits to using DDNS include:

Accessibility. Dynamic DNS lets you access home devices on your network from anywhere, as long as they have an Internet connection.
DHCP support. Dynamic DNS works seamlessly with DHCP, ensuring that devices with dynamically-assigned IP addresses can be reached regardless of IP changes.
DNS automation. Updating your DNS records is a time-consuming process. However, dynamic DNS automates the process, which saves you time and ensures up-to-date domain-to-IP mapping.
Cost-effectiveness. Static addresses can be expensive. Dynamic DNS eliminates the need to purchase static IP addresses from your Internet service providers (ISPs). By using it, you achieve functionality at a lower cost, making it an economical solution.
Cloud support. The IP addresses of cloud-based resources change periodically unless assigned a static IP address. DDNS updates the DNS records of cloud-hosted services to maintain accurate mappings.

Security risks of dynamic DNS

While DDNS can indeed provide a convenient way to access your network resources, it's not without risk. Make sure to consider the potential security threats that come with using dynamic DNS, such as:

Malware. Malicious actors leverage malware programs to hijack DDNS accounts. This could allow the malware to take control of the DNS update mechanism. However, if you configure your hostname with dynamic DNS, cybercriminals can easily change IP addresses to access your network resources.
Phishing attacks. Hackers can target DDNS with phishing attacks. If your organization uses DDNS, a scammer may use phishing sites to fool you into believing the websites are real. Then, this can compromise your company's resources.
DDoS attacks. If an attacker gains control of DDNS infrastructure, they may be able to launch DDoS attacks, making your website inaccessible.
DNS hijacking. Updating DNS records dynamically introduces the risk of DNS hijacking. Attackers may attempt to intercept DNS updates and redirect the domain to a malicious server.

However, several DNS security solutions provide protection against threats to DDNS systems. These mitigation strategies include:

identifying malicious DNS entries,
monitoring DNS infrastructure,
securing the DNS protocol and channel,
using secure and encrypted communications channels for dynamic updates,
employing DNSSEC to protect against DNS spoofing, and
only using DDNNS services from reputable providers.

Therefore, by adopting these measures, you can help protect your DDNS account from hackers.

What's the difference between DNS and DDNS?

Both DNS and DDNS implement lookups from domain names to IP addresses. The two services are almost identical; however, there is a difference in the frequency at which the DNS server's records are updated.

The domain name system keeps records of domain names and their associated IP addresses. However, it doesn't automatically update when a domain receives a new IP address.

The dynamic domain name system, on the other hand, automatically records any changes made to your IP address. Record updates happen more frequently so that DNS clients can access the most accurate information.

Frequently asked questions

What is dynamic DNS update?

DNS dynamic update is a feature of the domain name system that allows clients to update their DNS records without having to contact an administrator. In short, it simplifies the management of DNS records for your devices.

What is dynamic DNS used for?

Dynamic DNS services are used for IP address management. They are most useful where static IP addresses aren't an option, such as in homes or small businesses.

What are the best dynamic DNS providers?

Popular DDNS providers include DynDNS, No-IP, Heroku, DuckDNS, and Cloudflare DDNS (Cloudflare dynamic DNS).

What are the most common uses for dynamic DNS?

The most common uses for DDNS servers are accessing home or office networks remotely, sharing files, monitoring security cameras, and other home automations.

Does dynamic DNS use the same port as DNS?

Yes; both use UDP/TCP port 53.