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Universal Plug and Play: Friend or Foe?

We get a lot of technical support requests regarding Port Forwarding, the process of allowing access through the firewall on your router to your camera so that you can access your camera from across the Internet. It’s a tricky process which can leave many novice users scratching their heads.

Enter Universal Plug and Play

Universal Plug and Play (UPnP) is a set of network protocols designed to allow network devices to automatically communicate without any manual intervention from the user. In the case of IP cameras, UPnP often provides an icon on your computer to let you easily navigate to the camera as well as automatic port forwarding so that you can access your camera quickly and easily from anywhere in the world without any configuration.

Don’t confuse UPnP with Dynamic Host Control Protocol (DHCP). DHCP is the system which automatically assigns your computer or IP camera a unique IP address on your network. The two systems are completely independent.

How does it work?

In order for UPnP to work both the IP camera and the router need to support it. You can usually find out in the manual or datasheet of the item whether it is or not.

As soon as UPnP is enabled the camera will advertise itself across your network as a new device. Your router will then respond and provide its location and a description of its capabilities. Once received, your router will then automatically allow access from the Internet to your camera so that you can access remotely.

Most routers have a table for port forwarding. This is essentially a list of port numbers and local IP addresses. When data is received from the Internet the router checks the port number included. If the port number matches a port in the list the information is passed on to the corresponding local IP address. If the port number does not match anything the information is discarded.

The UPnP software in your camera passes the port number and IP address to your router to create a rule in the routing table. Sounds simple doesn’t it?

Does it actually work?

As with all computer-related features, sometimes. In perfect conditions UPnP is fantastic for novice users and lets them access remotely without any configuration.

However, conditions are not always perfect. In the real world routers and IP cameras can sometimes restart automatically. Network connections, especially wireless, can drop temporarily causing the camera and router to lose connection. There is a wide array of possible trip-ups for UPnP hardware which, once disconnected, will not reconnect.

One example customer had a camera where every day at around 2am the camera would stop functioning remotely. Every day without fail the same thing would happen and would not resolve until the camera was restarted. We eventually found out that his router was automatically restarting itself once a night which was knocking off the UPnP connection. Once the camera was restarted it was renegotiating the connection and worked fine.

Do I want to use it?

We would really recommend against it unless you have no other alternative.

Imagine you have just bought yourself an IP camera to keep an eye on your office while on vacation. The first day you log in and everything is fine but the second day the connection has dropped and you can’t access. You have to spend the rest of your holiday wondering if your office is OK and why you bothered to buy a camera in the first place. These days security is critical. An element that introduces even a little uncertainty simply can’t be trusted.

Is there an alternative?

The best method for port forwarding is to set up the ports manually. This takes all the control away from the automatic features and lets you specify exactly where information is to be sent. You can turn everything on and off as much as you like but so long as both your router and camera are turned on, the information will be forwarded as you have specified.

In order to setup port forwarding you need to know what port number and IP address your camera is on. Then log into your router by typing its IP address into a web browser. There are many different names you should look for when setting this up such as Port Forwarding, Virtual Servers and Port Mapping. Once you find the page, create a new rule for the port of your camera and enter the local address of your camera. Job done.

There are lots of guides on the Internet to help you if you get stuck. Alternatively have a look at our port forwarding guide as well as Portforward.com which offers walkthroughs for hundreds of different router models.

Published on February 8th, 2010 by James Drinkwater

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