Article Summary
- Your router, the DUC, or another DDNS-capable device detects an IP change and sends it to No-IP using your DDNS Key.
- The DUC is free for Windows, macOS and Linux, but the device running it must stay on and online.
- You do not need the DUC if your router has No-IP built into its DDNS settings.
- Dynamic DNS does not open your network; you still need port forwarding or a tunnel, and it does not bypass CGNAT.
- If DDNS stops updating, check that the DUC is running or that your router's DDNS setting is enabled.
No-IP Dynamic DNS keeps a hostname like yourname.ddns.net pointed at your changing IP address. This guide shows how the pieces fit together and how to set them up. New to the idea? Read What is dynamic DNS? Not sure you need it? Read Do I need dynamic DNS?
Key terms
- IP address: the number that identifies your connection on the internet.
- Hostname: a name like yourname.ddns.net that points to an IP address. What is a hostname?
- DNS record: the entry that stores which IP address a hostname points to.
- DDNS Key: a username and password for a hostname, separate from your No-IP login, used by your router or update client. How to set up a DDNS Key
- Dynamic Update Client (DUC): No-IP’s free software that reports your current IP address.
How No-IP Dynamic DNS works
- Your ISP assigns your network a new public IP address. This can happen after a router restart, a power outage, or on a schedule set by your ISP.
- The No-IP DUC, or your router’s built-in DDNS setting, detects the change.
- It sends the new IP address to No-IP, authenticating with your DDNS Key.
- No-IP updates your hostname’s DNS record, usually within seconds.
Diagram: IP change → DUC/router → No-IP → updated hostname. Alt text: “Diagram showing an update client sending a new IP address to No-IP, which updates the hostname’s DNS record.”
Three ways to keep your hostname updated
- Your router. Choose No-IP in the DDNS settings and enter your DDNS Key details. How to configure DDNS in a router
- The No-IP DUC. Free for Windows, macOS and Linux. The device running it must stay on and online. Download the DUC
- Another DDNS-capable device, such as a DVR, NVR or camera system.
What dynamic DNS does not do
- It does not open your network on its own. You still need port forwarding, or a tunnel such as No-IP Public Tunnels that works without it.
- Dynamic DNS doesn’t bypass carrier-grade NAT (CGNAT). If your ISP uses CGNAT, inbound connections can be blocked even when DDNS is set up correctly. What is a CGNAT IP address?
Get started
- Create a free No-IP account.
- Create a hostname with the Getting Started guide.
- Create a DDNS Key, then set up your router or download the DUC.
- Set up port forwarding
Frequently asked questions
It’s a service. No-IP runs the DNS servers for you. You create a hostname and keep it updated.
No. If your router has No-IP built in, it can send updates directly.
Yes. No-IP offers free hostnames, and paid plans add more features. See Compare plans for current details.
In your No-IP account, select or create your hostname and enable Dynamic DNS. Follow the prompts to create a DDNS Key, then enter its username and password in your router, the DUC, or another DDNS-capable device. See How to set up a DDNS Key.
DDNS only keeps your hostname current. Safety depends on your router password, port forwarding rules, firewall and encrypted connections such as HTTPS, VPN or SSH.
Remote access stops working, because your hostname still points to your old IP address. It starts working again once the DUC or your router detects the change and sends the update. Check that the DUC is running or that your router’s DDNS setting is enabled.