What is Dynamic DNS?

What is Dynamic DNS?

Dynamic DNS, or DDNS, keeps a hostname pointing to the current public IP address of a connection that may change.

It is useful when you have an office, router, camera, server, NAS or another Internet-accessible service, but your provider does not give you a fixed IP address.

Instead of remembering the IP address, you can use a name such as test.example.com or vpn.example.com. When the IP changes, the DDNS client sends an update and DNS publishes the new IP.

Short answer

DDNS is a way to update a DNS record automatically when the public IP address of a connection changes.

If you have a fixed IP, you usually do not need it.

If you have a dynamic IP and want to always reach the same place with a stable name, DDNS avoids having to check the IP every time it changes.

When should you use DDNS?

DDNS is useful when you need to reach a connection with a changing IP.

Common cases include:

• remote access to an office;
• VPN connections;
• routers with dynamic IP addresses;
• cameras or security systems;
• carefully exposed internal servers;
• devices that must update their DNS record automatically.

You do not need DDNS if you already have a fixed IP address and the DNS record does not need to change.

What is it useful for in practice?

DDNS gives you a stable name to reach a connection even when the IP changes.

For example, you can configure vpn.yourdomain.com so it always points to the current public IP address of the office router.

When the provider changes the IP, the router or a program on your computer calls the DDNS service and tells it the new IP. DNS updates the record and the name points to the right place again.

What is the difference between DNS and DDNS?

Normal DNS publishes records that you change manually from the panel.

DDNS is an automatic update of a specific DNS record, made by an authorized device or client.

The final result is still a DNS record. The difference is that the value can be updated often, without signing in to the panel each time the IP changes.

What should you know before enabling it?

Before enabling DDNS, decide which hostname you want to update.

For example:

• vpn.yourdomain.com;
• office.yourdomain.com;
• camera.yourdomain.com;
• test.yourdomain.com.

You should also know that DDNS updates a public IP address. It is not meant to publish a private IP such as 192.168.1.20, because that address only exists inside your local network.

If there is a camera, server or NAS behind the router, you usually also need to configure the router to forward traffic to the correct internal device.

How is it used?

The device that knows the public IP, usually the router, must call an HTTPS URL on the DDNS service.

The request includes:

• the hostname to update;
• the IP to publish, or the instruction to use the public IP of the connection;
• the DDNS username and password.

Many routers have a Dynamic DNS, DDNS or similar section. If the router allows a custom update URL, you can use the PRIMARI.NET update URL.

How to configure Dynamic DNS (DDNS) at PRIMARI.NET

At PRIMARI.NET, DDNS is a free option included with the primary DNS service.

To use it:

1. Sign in to the PRIMARI.NET panel.
2. Open Primary DNS.
3. Edit the domain.
4. Click Manage DDNS.
5. Enable DDNS if it is not already enabled.
6. Save the username and password shown by the panel.
7. Click Activate changes in primary DNS.
8. Configure your router or DDNS client to call the update URL.

What do you need before configuring it at PRIMARI.NET?

The primary DNS service must be active for the domain.

DDNS permission is granted for the whole domain. This means the domain credentials can update hostnames inside that domain.

How to enable DDNS at PRIMARI.NET

1. Open Primary DNS

Sign in to your PRIMARI.NET account and select Primary DNS from the main menu.

If the domain does not yet have primary DNS, enable that service first. DDNS is part of it.

2. Edit the domain

In Manage your domains, click Edit next to the domain.

The panel will show the DNS configuration and a Dynamic DNS (DDNS) section.

3. Open DDNS management

Click Manage DDNS.

This opens the DDNS page for the domain.

4. Enable DDNS

If DDNS is disabled, click Enable DDNS.

The panel automatically generates:

• a username;
• a password;
• a pending activation request.

The panel keeps showing these connection details so you can copy them to your router or DDNS client.

5. Activate DNS changes

Return to primary DNS and click Activate changes.

Until changes are activated, the DDNS configuration remains pending and is not yet published to the final service.

Update URL

The DDNS client must call an HTTPS URL on the PRIMARI.NET DDNS service.

To assign a specific IP:

https://ddns.primari.net/jqbddns/update.pl?hostname=host.yourdomain.com&myip=1.2.3.4

To use the public IP from which the request is made:

https://ddns.primari.net/jqbddns/update.pl?hostname=host.yourdomain.com&use_remote_addr=1

The request asks for the DDNS username and password shown by the panel.

Replace host.yourdomain.com with the real hostname you want to update.

How to test it

The DDNS page in the panel provides two test links for test.yourdomain.com:

• assign the test IP 1.2.3.4;
• assign the public IP of the computer you are using.

When you click one of these links, the browser asks for the DDNS username and password.

Then you can check the result with:

C:\Users\User>nslookup test.yourdomain.com

If the record does not show the expected IP yet, wait a short while and try again. Some resolvers can keep cached DNS answers for a while.

Changing the password

To replace the password, open Manage DDNS and click Generate new password.

Then update the password in the router or DDNS client and activate the pending primary DNS changes.

Disabling DDNS

To stop allowing DDNS updates for the domain, open Manage DDNS and click Disable DDNS.

Then activate the pending primary DNS changes.

Common mistakes

Common mistakes include:

• not activating changes after enabling DDNS;
• configuring the router with an old password;
• entering a hostname outside the domain;
• writing the domain twice in the hostname;
• testing DNS too early and still seeing an old answer;
• confusing the device private IP with the connection public IP.

When to contact PRIMARI.NET

Contact PRIMARI.NET if you are not sure which hostname to use, if your router does not accept the update URL, if nslookup does not show the expected value or if you want us to review the configuration before publishing it.