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Dynamic DNS, or Do I Really Need a Static IP Address?

When you install a new IP camera it is most likely that you’re going to want to view it from outside of the network on which it’s installed – your local network. To do this you need two things:

  • You need to know your external IP, or WAN address
  • You need ‘port forwarding’, or Network Address Translation (NAT) rules active on your router

Why does it have to be so complicated?

It doesn’t. Your WAN, external, or public IP address (all terms for the same thing) is the internet protocol number which links your broadband router or modem to the Internet. It is the gateway through which all network traffic exits, or crucially in this case, enters your network. You need to know this address to be able to connect back into your camera.

You can very quickly discover what this address is with a quick visit to any site which can display your WAN IP such as www.mycamip.com. Once you know this address, the fun really starts!

It’s a safe bet that unless you know you have a static IP address, you’ll have a dynamic WAN IP – one that changes on a regular basis, perhaps even each day. This clearly makes it difficult to connect to your camera conveniently when you’re away since you need to be at your actual local network to determine what your external IP address is. Sheesh….

And the answer is….

You could simply ask your ISP to assign you a static IP address, but this is not always possible. The answer lies with Dynamic DNS (DDNS).

DDNS is a fancy way of saying that an IP address (like is translated to an easy to remember domain, or hostname like mynewwebcam.viewnetcam.com each time it changes. The DDNS system knows that the new IP needs to be assigned to the hostname.

Here you have another choice: do you use the DDNS service built into the camera (if supported), or use a third-party DDNS service such as DynDNS or NO-IP. Our preference is for DynDNS (we like to call them din-dins…), but some of the others are just as reliable.

The downside with DDNS services is that whenever the WAN IP address changes the DDNS service must be notified. This is either done automatically by the camera, or perhaps the router supports DDNS. A third option is to run a DDNS client on a PC which can update the service. In all likelihood the router will support DDNS if the camera does not.

DDNS automagically by camera

Some IP cameras already have DDNS services installed, often provided by the manufacturer themselves. In particular, Panasonic provide their Viewnetcam.com service and Axis their Axiscam.net service. Both services work in the same way. The camera watches for WAN IP address changes and notifies the DDNS service of the new IP address. On-camera DDNS is often the most reliable way to ensure a permanent connection to your camera.

More complication. Or is it?

Once your DDNS service is in operation the last step is to ensure that when you access your WAN address it is the camera you see and not something else. You do this by setting up ‘Port Forwarding’ or ‘Network Address Translation’ rules on your router. These are names for the essentially the same thing. You can find instructions for how to do this on your router at the helpful website www.portforward.com.

A further option is to place the camera’s IP address in the DMZ for the router. Every broadband router or modem has a DMZ (short for De-militarized Zone). Once in here your camera will receive any traffic entering the router from your WAN IP address. Whilst this is not a security risk with most cameras, it is worth noting that all ports and protocols are accessible in this way. It is always advisable to forward a single port number to your camera, rather than all ports.


Whilst DDNS setup seems complicated it’s really not that involved. For the most part the whole dirty process can be managed from the camera. Panasonic’s Viewnetcam.com service in particular is very easy to use and highly reliable and is highly recommended. For the simplest operation, however, your router should support Universal Plug and Play (uP&P) since the camera will automatically set up the port forwarding rules for you (they’re very clever).

Dynamic DNS has finally come of age and is not only ideal for the home user, but is now suitable for businesses use as well. We use it and so should you.

Published on January 9th, 2007 by Kevin Bowyer

7 Responses to “Dynamic DNS, or Do I Really Need a Static IP Address?”

  1. Bhushan says:

    My machine is connected to LAN with router having public IP which is connected to internet.
    Now my machine has IP address assigned by LAN (e.g. But public IP of the network from ISP is something like

    So whenever I check my ip address (on whatsmyip.net/) it gives IP address of router(which is public IP),

    My requirement is to have TCP communication between external machine having IP address lets say "" and my machine "".

    I have tried various DDNS tools such as NO-IP, DynDNS. But all of them are taking IP address of router.

    My confusion is how to tell the router that whenever any request is received for Port no 5001, route it to my local machine.

    Thanks in advance !!!

  2. numan says:

    but it did not work i have static ip

  3. numan says:

    how it can work

  4. Rob Jackson says:

    Hi, been onto Interwatch Security and they have now been taken over by http://www.sebsltd.com.

    We have made some enquiries about our holiday home in Cyprus and the price appears to be much cheaper than IWS. They avoid using expensive phone lines and ADSL connections

  5. Simon Hodges says:

    I use no-ip.biz with our IP camera in Cyprus. We use a PC over there which updates the IP address so the Interwatch system works at treat.

  6. KB says:

    Many routers will actually have the capability to update a dynamic DNS account, so you may not 'need' a static IP address at all. Some ISPs will not be able to allocate static IPs either.

  7. David Robson says:

    You need a static IP address if you are running the camera from a router and don;t have a pc to update the IP address. We use a static IP address for our property in Cyprus. Cyta charge only a few pounds a month for a static IP. For us this is the way we need this to work. Using the Interwatch Security system for our Cypriot home this works out well for us. They use a very sophisticated peace of software to enable us to be able to view our home 24 hours of the day. The alerts we get at 3am are no fun though!