Dynamic DNS: what is it and why do you need it?

When a changing address causes problems

Most home internet connections are assigned a dynamic IP address — one that changes from time to time: when the router is restarted, due to maintenance work carried out by the provider, or simply over time. For normal web browsing, this goes unnoticed: you open a page, and the website’s server finds you automatically using your current address.

The problem arises when you need someone to find you specifically — for example, if you want to access your home security camera from your mobile whilst you’re out and about. The address you memorised yesterday may already lead nowhere today.

To understand how DDNS solves this problem, let’s first look at what a standard DNS is. It’s a sort of phone book for the internet: it maps human-readable names (such as google.com) to numerical IP addresses – which are difficult to remember – via which the actual connection is made. Thanks to DNS, you don’t need to keep a string of numbers in your head – you simply need to type in the website’s name.

Standard DNS works well as long as the address remains stable. But if the entry in the phone book is out of date — the subscriber has moved, the number has changed, and nobody has updated the book — you won’t be able to get through.

Dynamic DNS works on the same principle as a telephone directory, except that there is a «secretary» who keeps track of changes and instantly updates the entry whenever your IP address changes. Instead of having to remember a string of numbers, you use a permanent, unchanging address such as mydevice.ddns.net — and the DDNS service works in the background to ensure that this address always points to your device, regardless of which IP address has been assigned to it at that moment.

How DDNS works in practice

A small client programme from the DDNS service is installed on your router or device. As soon as your internet service provider assigns a new IP address, the client detects this and immediately notifies the service: «My address has changed; please update the record». The service updates the mapping between your domain name and the new address — this usually takes just a few minutes.

To anyone trying to connect to you, the whole process is transparent: they simply enter a standard name, and the DDNS service automatically substitutes the current address behind the scenes, without any intervention from the user.

Advantages of DDNS

First and foremost, DDNS is convenient because it takes care of the routine tasks: the user does not need to check for a new IP address every time or change the settings whenever it is updated. This offers the user several practical advantages:

1. A permanent address for connecting. Instead of a string of numbers, you can use an easy-to-remember domain name — for example, myhome.ddns.net. This remains the same, even if your internet service provider assigns a new IP address.
2. Automatic updates. The DDNS client automatically notifies the service of any changes to the IP address, so there is no need to check it manually after every router reboot or change made by the ISP.
3. Cost savings. If the sole aim is to have a permanent address for remote access, DDNS can be a cheaper alternative to a static IP address. Some services offer free options.
4. Convenient remote access. This technology is useful for connecting to home cameras, NAS devices, VPNs, servers, smart home systems and other devices that need to be accessible via the internet.

Drawbacks and limitations of DDNS

However, like any network solution, this technology has certain characteristics that are worth bearing in mind before setting it up:

1. DDNS is not a substitute for a static IP address. The service itself merely monitors changes to the address and updates the DNS record. If a fixed IP address is specifically required for a particular network configuration, DDNS will not solve this problem.
2. DDNS support is required. The router or other device must be capable of working with the chosen service. If there is no built-in support, a separate client programme will be needed.
3. Not all connections allow DDNS to be used for incoming connections. If your internet service provider uses CGNAT (Carrier-Grade NAT), several subscribers may access the internet via a single shared public IP address. In such a situation, DDNS may update the record correctly, but a direct connection to your home device from the internet will still not work.
4. DDNS does not increase speed or protect your network. It merely helps locate a device via a permanent domain name. Security must be ensured separately — through strong passwords, up-to-date firmware, a VPN and correct access settings. Similarly, DDNS does not resolve issues with the internet connection itself: if the connection is unavailable, you will not be able to connect to your home device regardless of the domain name.

Who needs DDNS and why

The technology itself sounds rather abstract, so it’s worth looking at specific situations where it’s actually needed:

• Remote access to home devices. If you’ve set up remote access to cameras, a NAS or your home computer via port forwarding or your own VPN, DDNS removes the main inconvenience of this approach — you no longer need to check your current IP address every time before connecting.
• Home servers. If you’re running a gaming server, media server or file-sharing server at home, friends or colleagues will be able to connect via a single, fixed address without having to ask for the latest figures every time.
• CCTV systems. Cameras that need to be accessible from outside the home 24/7 are most often configured via DDNS — this is the simplest way to guarantee stable access without resorting to more expensive alternatives.
• Small personal projects. If you want to host a personal website or service directly on your home equipment, without renting hosting, DDNS allows you to do so without significant investment.

Dynamic DNS vs. Static IP Address: Which to Choose?

It is worth distinguishing right away between two similar yet distinct solutions to the same problem.

A static IP address — available through your service provider — is an address that never changes. It is more reliable but is usually offered as a separate paid service.

Dynamic DNS addresses the same need differently: your IP address may continue to change as often as it likes, but a permanent domain name makes this transparent to anyone connecting to you. This is a more cost-effective option that works perfectly if you simply need a reliable way to connect, rather than a fixed address per se.

In practice, these solutions are often combined: a static IP offers maximum reliability and slightly simpler initial port configuration, while DDNS provides a more budget-friendly way to achieve virtually the same result.

How to get started with DDNS

Most modern routers have built-in DDNS support in their settings — usually in a section with the same name. You need to register with a DDNS provider (free options are available), obtain a personal domain name, and enter your account details into the router's settings. The router will then automatically monitor its IP address and notify the service of any changes — without requiring further intervention on your part.

Popular DDNS providers include:

• Duck DNS. This is a completely free and simple service built on Amazon AWS infrastructure. It allows you to create up to five domains in the .duckdns.org zone and is supported by most routers and scripts.
• No-IP. A well-known provider offering a free plan that allows you to create up to three domains (choosing from several domain zones). The main requirement for the free version is to confirm account activity every 30 days via a link sent in an email.
• ClouDNS. A reliable DNS provider offering free dynamic DNS support (up to 4 servers, 1 zone, and 50 records). It supports both IPv4 and IPv6.
• Cloudflare. If you own a registered domain, you can use Cloudflare’s DNS for free and dynamically update your IP address via their API using scripts or the ddclient utility.

Additional considerations

While DDNS solves the addressing issue, it does not replace other necessary steps for setting up secure access. If you plan to open ports to the outside world for cameras or a server, it is advisable to use strong passwords on all devices and keep your router’s firmware up to date; DDNS simply makes it easier to locate your device — it does not provide security on its own.

Connection stability is also crucial: if the connection drops frequently, the DDNS record must be updated more often, and access to the device will be temporarily lost during the outage, regardless of how the address is configured. The Maksnet fiber-optic network, based on GPON technology, ensures a stable connection — avoiding the speed drops typical of congested network segments — even during peak usage hours. However, for services like DDNS, cameras, or home servers, connection stability is of paramount importance.