Dynamic DNS (DDNS) Troubleshooting Guide

Having trouble connecting to your device? Check out this Knowledge Base article for answers to some of the most frequent issues.

Does the IP address my hostname is resolving to match my current public IP address?

Login to your No-IP account and navigate to My Services > DNS records on the left side menu of the page. You will see a list of domains/hostnames that are associated with your account. Next, to the hostname, you will see the IP address that we are currently resolving to. You can verify that this is the correct IP address by visiting Port Check Tool. This website will show you your current public IP address. If the IP address does not match the one listed by your hostname, you will need to manually update it to get your service working again.

How do I manually update my hostname in my No-IP account?

To manually update the hostname, login to your No-IP account and navigate to My Services > DNS records on the left side menu of the page. Next to the hostname that you need to update click “Modify”. On the next page, under the Hostname Information window, you will see a location to change the IP address. Replace the IP address being shown with the IP address you received from Port Check Tool and click Update Host at the bottom right of the page. It will take 60 seconds for the changes to fully propagate to the new IP address.

How do I avoid manually updating my hostname in the future?

In this situation, it is recommended to use an update client that will automatically update the hostname’s IP address when it changes. You will need to download No-IP’s Dynamic Update Client. This Dynamic Update Client will track any changes to your IP address and allow No-IP to update them accordingly. You can also check to see if your device (router, camera, etc) supports Dynamic DNS and has No-IP as an integrated provider. If it supports No-IP, you can configure it to update your hostname with the correct IP address. This removes the need for downloading our Dynamic Update Client.

Note: This software must be installed and running at all times in order to continue sending us an update. If the update client gets turned off, or if the computer is shut down or falls asleep, the update client will stop working and we will not receive any updates.

Is the DNS server returning the right IP address?

If your hostname is showing the correct IP address, but you cannot connect to your device, the next step is to make sure that the hostname is resolving properly. The easiest way to test this is to run an NSLOOKUP command from a Terminal window. Open a command line window (Terminal on Linux, Command Prompt on Windows) and type the following: nslookup yourhost.yourdomain.com.

In response, you should see a message that looks similar to this:

Screen Shot 2015-06-08 at 10.40.16 AM

The IP address that returns should match the IP address that is shown next to your hostname on the Hosts/Redirects page.

How do I configure my router to remote access my device, computer, etc?

First, you need to configure port forwarding on your router. You will need to know what port your application uses, and also the internal network IP address of the machine you’re using to serve that application. Have a look at our Basic Port Forwarding Guide for more information on port forwarding.

Note: You should only open the ports that are needed to gain access to your applications. You will also want to make sure your computers have all the latest patches and security updates applied, in order to minimize the possibility of someone compromising your network.

What if my computer has a firewall enabled?

If your computer has a firewall turned on, you will need to configure it to allow inbound connections. If this is not set up properly any inbound connection of your network will fail. Among the more popular firewalls, is the one built into Windows-based computers. We have an illustrated guide that covers how to configure that firewall here. Please consult the documentation for your product to find specific instructions on how to configure its firewall service

Is my ISP blocking the port(s) I am trying to use?

The easiest way to test if your ports are open and properly configured on your end is to use our Port Check Tool. Simply put the port number you want to test, 22 in our example, in the box marked What Port?, then push the Check button. Our server will attempt a connection directly to your IP address and let you know the results. Anything other than a response like the one below indicates something is wrong.

Screen Shot 2015-06-08 at 10.40.06 AM

A response that says “Connection Timed Out” usually means that your router isn’t properly set up, or that your ISP is blocking the port you’re trying to use. Double-check your port forwarding configuration and repair it if need be. If it looks right and you still can’t connect, try running your service on a different port and try the test again.

A response of “Connection Refused” is indicative of a potential firewall problem.

What if a port is blocked?

If it turns out that the problem is being caused by your ISP’s port block, you have a few options available. In the case of a web server being denied access on port 80, you can use the Port 80 Redirect feature of our Dynamic DNS service. The Port 80 Redirect is available as a part of any of our Dynamic DNS and Managed DNS packages. This allows you to specify a different port for your website to use and is transparent to your users.

If the ISP is blocking port 25, which is used to run an SMTP mail server, then we have different options depending on whether the block is outbound or inbound. You can find these answers in our knowledge base.

If you have any additional questions or if this didn’t solve your problem please feel free to open a support ticket.