Service Selection and Updating Methods for DDNS

Joe Loucks

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On November 1st In IP Solutions, Video Surveillance
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Before an installer can set up a DDNS for a client, the provider of the DDNS must be selected. DDNS has been available on the Internet for decades, and there are a number of “public” DDNS providers. Typically these public services charge a nominal fee such as $20US for annual service for one account. Two of the most popular public DDNS providers are TZO.com and dyndns.com.

Many electronic security device manufacturers are also providing DDNS services, usually at no cost to dealers.

Whether the DDNS service is public or provided by a manufacturer the functionality will be the same, provided that the updating method is properly programmed.

When using a public DDNS service, the first step is to establish an online account on the DDNS service chosen. For this example we will be using dyndns.com. The account setup is straightforward, and you’ll be prompted to establish the URL or “domain name” that the client will use to access the account. Once you’ve selected the URL such as “bobsdvr.dvrdns.com” you will soon receive an email indicating that you can use that particular name. If another DDNS client has already claimed that name you will need to select another that’s unique on that service.

Once the domain name is approved, the service is ready to be established. Now a device within the local network must be programmed to update the DDNS. Optimally the device doing the updating is always turned on and connected to the target LAN. Many common routers have programming fields that can provide DDNS updating capability for the major services such as TZO and dyndns. If planning to use the router for DDNS updating, installers must verify that the router actually “sees” the true public IP address. In many cases the router will see the local-side address of the DSL adapter or cable modem, and not the actual public IP. This can be verified by entering the router’s programming and looking at the current “public” or “Internet” IP address. If this address is a “private” IP which typically start with “172.16.” or “192.168” the router doesn’t see the actual public IP address. If you are not sure whether the address is private or not, open a web browser on a PC that’s connected to the target LAN and input www.whatismyip.com. This will provide the true public IP address currently used by the target network. If it doesn’t match the “Internet” address indicated in the router’s programming that device cannot be used for the updating function.

Dyndns provides an updating software that can be installed onto a client’s PC to perform the Public IP updating function.

In the case of public DDNS services, a small software application can be loaded onto a PC that is connected to the target LAN.  Such a program is illustrated above. This program runs on startup and constantly checks the public IP address; if the IP address changes this program will sign on to dyndns.com with the username and password and then update the IP address on file.  Obviously if the PC is turned off no updating will occur.

When using a vendor-supplied DDNS service the security device is connected to the LAN with a proper static LAN IP. After the connection installers can set up the DDNS by accessing the programming of the security device and following the required steps. Installers should verify that the DDNS updating has been set up properly and is functional. Usually dropping the power to a DSL or cable modem for 30 seconds and then reapplying it will reset the DSL with a new public IP address. It may take 15 to 30 minutes for the updating to be completed.