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Using DDNS to Deal With Changing IP Addresses

A public IP address is the network version of a phone number to your router
This article is written for a residential customer who is trying to configure their DVR for remote internet access. In order for client software (like PSS) or a web browser pluggin to connect to a network DVR, it must know the public IP address of the router that is connected to the DVR. This IP address is also sometimes called an external IP because it is outside and separate from the local area network (LAN).  It is like a unique phone number that allows one network device to connect (or call up) another device. As a general rule, when most busineses obtain an internet service account they are issued at least one fixed IP address. "Fixed" means that the IP never changes and it can reliably be used to establish a connection to our router.

However, for the residential customer difficulty often arises because ISPs typically do not default to issuing a fixed IP address.  Moreover, it is not unusual for them to force the IP address of your router to change frequently.  While not officially stated, it is their hope that customers will elected to pay a monthly fee for a fixed IP address which can sometimes exceed $12.00 / month.  Boo!

Dynamic Domain Name Service (DDNS) to the Rescue!
DDNS is method to create and maintain a host name such that it will always resolve to the current external IP address of your router.  Once created and setup, the host name can then be substitued everywhere client software (including a web browser) calls for the entry of an IP address.  The host name looks identical to a URL you might type in your browser.  For example, "myrouter.webhop.net". Another network service called DNS (just plain Domain Name Service), is the mechanism that actual resolves or translates the host name / URL to an explicit IP address at the time communication software needs it.

In a nutshell, DDNS is the creation and maintenance of a host name / URL that will constantly be updated to resolve to the current external IP address of your router--no matter how frequently your greedy ISP decides to change it.

Is this DDNS going to cost me more money?
More good news--there are a number of commercial websites that offer a free DDNS service to the public in order to make potential customers aware of other paid services they offer.  A couple of these companies have been around long enough (many years) to prove that they are reliable and easy to work with. Subsequently, many router manufacturers and our QV Series DVRs now offer direct support in their firmware for these free DDNS services. For the tutorial below, the company we are going to use as an example is no-ip.com.

How does it work?
Once the user signs up for the free service and a host name is created and activated, maintenance of the DDNS is done by two pieces of software talking to each other. The first piece is the client software that is located within the private or local area network. In our case this utility software resides in the DVR firmware, but it could also be activated within a supported router or run on a PC. The job of this client software is to monitor the external IP address for change. If your ISP changes the external IP address of the router, it contacts the DDNS host server (example, No-IP.com) and sends the new IP to update the host name / URL.

Great! Now how de we make all this magic happen?
Now that we have the why and theory of DDNS under our belts, we can explicitly explain the 3 mains steps:

a) Making sure plain DNS is properly configured in the Network Setup section of the DVR.
b) Signing up, creating, and activating your No-IP.com host name / URL.  We'll also verify that it is working.
c) Configuring DDNS in the Network Setup of the DVR.

Step 1:  Configure DNS Before We Begin...Important!
It is very important to configure "DNS" under Network settings before we begin.  DNS is the mechanism that resolves / converts server names & URLs into useable IP addresses. The DVR doesn't automatically figure out the IP addresses of your Internet Service Provider's Dynamic Name Servers. You need to configure this first because the DDNS service on the DVR needs convert the host name that we enter later.  Luckily, this is not hard to do with the proper guidance.  Please click here for a tutorial on DNS configuration if you haven't already completed this crucial step.  As a side note, DNS also needs to be configured in order for the DVR to interface with a Email Alerts or any server name for that matter (NTP, FTP, etc.).

Step 2: Start the Process to Create a Free Account at No-IP.com
For this demonstration we're going to use No-IP.com. Before we attempt to create a DDNS host name, it will be necessary to create a free account.  Go to No-IP.com:

 Click "Create an Account"

No-IP.com home page

Step 3: Select Free DNS

no-ip.com account creation

Step 4: Fill Out & Submit Form
This form is fairly straight forward--check out the sample entry below.  Click the Create Account button to proceed.

no-ip.com account creation

Please record / save your User Name and Password to a safe place.  They will be needed later when we configure the DVR to send new IP addresses to the No-IP website.


Step 5: Check Your Email & Activate Your New No-IP Account
Once the account is created, the following screen will display instructions to check for an email message that will contain a link to activate the account.

No-IP.com account activation


Step 6: Create The No-IP Host Name
Now that we have an active No-IP account, we can create our free Host Name.  To do this, click on the Add a Host button after logging in, or click here: Click Here to go to the Add New Host Name page:

no-ip.com account activation

In this example below, we are creating the following parameters:

hostname: my-home-router.no-ip.org
user name: MyUserName
password: some disguised value

Other fields are also examples: IP address (48.42.174.52), Security Question, Birthday, etc.

no-ip.com account activation


Please record your new Host Name to a safe place.  It will be needed later when we configure the DVR to send new IP addresses to the No-IP website.


Step 7: Configure Advanced Network Setting "DDNS" on the DVR
Finally, we can move to the DVR and configure and enable the DDNS update utility.  This is done by going to Main Menu-->Settings-->Network. From the Network Menu, follow these steps:

A:  At the bottom of the screen under "Advanced Setting", scroll down and double-click the line labeled "DDNS"
B:  Select "No-IP DDNS" from the top pull-down ment;  Make sure the "Enable" box is checked.
C:  Keep the defaults: "dynupdate.no-ip.org" for Server IP and Port 80.
D:  Enter the personalized Host Name that was created in Step #5
E:  Enter the No-IP User Name and Password that was entered in Step #3 when the account was created.
F:  Click "Ok" to close the DDNS menu and then "Save" to save and close the Network Settings.

Configure DDNS on the DVR

Whew! That's it!  Now, every 5 minutes (300 seconds) the DVR will talk to the No-IP servers to make sure your Host Name will resolve to the correct IP address of your router.


Sweeeeet!  But How Do We Know It's Working?  (Optional Reading)
In order to see if our Host Name is active and getting updated, we need a tool to see the router's external IP address and what IP address, if any, does our Host Name resolve to.

Fortunately,  there is a utility website that does this:   Network-Tools.com.

Your router's external IP address is displayed when the website first loads.  The "Lookup" feature (make sure the radio button is selected) can be used discover the resulting IP address of resolving Host Name or URL.  To do this, type in your Host Name and click the "Go" button.

If the Host Name resolves to your router's external IP address,  then is good.  We now know that at least No-IP has successfully registered and intitialized the Host Name.  However, we don't really know if the DVR is successfully talking to the No-IP server until the external router IP does not match what the Host Name resolves to AND the DVR then updates the Host Name to make the two match.

To test that the DVR is properly communicating with the No-IP server, do the following:

1.)  Visit the No-IP website and go to the Host Services Section: (you may have to login first).  

2.)  Click on your Host Name and change the last part of the IP address so that it now longer matches the router's external IP address.  Save the change.

3.)  Use the Network-Tools.com. website to verify that the Host Name and router IP address are out-of-synch.

4.)  Let's see if the DVR will correct the problem.  Restart the DVR or wait at least 5 minutes.

5.)  Go back to Network-Tools.com. and see if the Host Name and router IP address are back to being the same.

Hopefully they are and we can now celebrate.  Be patient though, sometimes the update process may take more time.   If the DVR isn't correctly updating,  then re-check your configuration setting in the last step.  Be aware though that one likely cause may be that you have not correctly configured plain DNS on the DVR, which was step #1.



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