Dynamic DNS zeroes in on IP addresses

FRAMINGHAM (10/03/2003) - Our sister-in-law Lydia runs a preschool and wanted to have a wireless Webcam so parents could see their little darlings. But first there was the problem of her Digital Subscriber Line (DSL) connection. One of the more annoying issues with consumer broadband links is the common use of dynamic Internet Protocol (IP) addresses. You get a different address each time you restart your connection.

While this is generally acceptable, it is a problem when you need to run a server - you can hardly serve anything if you can't be found. Let's say you are setting up a branch office, and you have a dozen people who want to pick up e-mail. Rather than having them all go out over a shared DSL connection you might decide to give them an in-house e-mail server that, because it is centralized, also lets you archive incoming messages.

So if the IP address is not guaranteed to be the same twice, what can you do? Well, dear reader, there is a simple answer: dynamic domain name server (DNS). Essentially this is a DNS server that can be updated frequently. At some computer at the branch location you run software called an update client that periodically talks to the dynamic DNS server and reports the current IP address. Voil...! The branch office now can be found.

There are many dynamic DNS servers on the 'Net. One we have used is DynDNS, owned by Dynamic DNS Network Services LLC. DynDNS provides a range of charged-for services, but it also offers free entries for up to five host names per person.

A name mapped to a dynamic IP address will be suffixed by one of more than 40 domains that DynDNS makes available - for example, spokaneoffice.gotdns.com.

We used an update client called DynSite to make our sister-in-law's preschool Webcam - a D-Link Systems DCS-100W Air 2.4-GHz wireless network Internet camera - accessible to parents through DynDNS.

The parents love it; one of them said she regularly gets to eat lunch with her child because of it. You can see D-Link's write-up of the school's use of its gear.

Getting the picture

The camera connects over 802.11b, or 10/100M bit/sec, Ethernet and can produce VGA video at up to 20 frames per second. Even when we were 30 feet from the wireless base station, which is surrounded by metal filing cabinets and with a wall in the way, we could reliably deliver streaming video across the Internet at around one frame per second.

The DCS-1000W has both automatic and manual modes for gaining control, exposure and white balance; and shutter speeds from 1/60 second to about 1/15000 second. It also will function down to an illumination level of 2.5 lux at f1.4.

The camera has a built-in Web server, and through the utility software you can set the frame rate and image size; and define users, their passwords and access levels. The actual imaging at the receiving end can be done via a Java applet or an ActiveX control. So far we have been unable to get the ActiveX component to work outside the LAN, but the Java applet works just fine across the Internet.

This camera has many more sophisticated features (all sorts of event triggers, including motion in the field of view and external devices) that make it a very good monitoring solution. The bundled software lets you monitor up to 16 cameras simultaneously. You also can record video to the hard-disk drive.

It was pretty easy to get running and configured, although as with all of these wireless products, the average non-technical user would have a tough time. The only complaint we have is that we can't "un-frame" the Java applet from the default Web page the camera generates. If we try to load the applet directly from the camera we can't authenticate, and therefore we can't receive the video stream. The problem with the default Web page is that it is techie - it has buttons to switch triggers on and off, which isn't relevant to what the parents want. C'est la vie. D-Link is, we hope, finding a fix for us.

All in all, a great product, and if we can get a fix for accessing the camera without the default Web page, it might even achieve a terrific rating.

Rate us at gearhead at gibbs.com.

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