My home network, like most, I suspect, has grown out of necessity. I admit to a fondness of rulers, coloured pens and diagrams, allied with whiteboards and planning bullet lists. One day, I may just properly plan out a network, but in truth, as a new device passes through my door, it's powered up, a blue cable attached and away (usually) we would go.

To date, I have an Acer 5000 laptop for everyday use, a hybrid desktop with twin monitors for video editing, another hybrid on a 27" TV/ monitor for gaming (that also has a Sony PS3 and XBOX connected), my wife's laptop via wireless and in a "rack", a Netgear NAS, DVICO NIX PVR, DLink DIVX translator and three printers. With a four port modem/router, this tended to get me by without any great problem (with a bit of swapping between the PS3/ Xbox and DVICO as needed). Wireless took care of the rest.

I know at this point you're asking why I don't run everything via wireless. Simple - wireless isn't as fast as cabled, and especially with video and publishing, I move some pretty hefty files around. Another good question is why not use a HomePlug system. That would be fine if the house was on a single phase. But my place was originally two houses joined together, so it's not guaranteed that two power points will 'talk' to each other. I have wireless access from my Asus Eee and Apple iTouch and that works fine for my needs.

Everything was going swimmingly until I added a Netgear VoIP phone and a MyNetFone. All the cabled gear was working fine, but wireless access became flaky and unreliable; devices could see the Budweiser network, but couldn't connect.

I did all the obvious things such as checking all connections, powering down and back up and so on. I also run some nifty network monitoring, logging and troubleshooting software called Network Magic which takes a lot of under the bonnet stuff out of your clumsy fingers and makes them automatic. For example, theoretically, if you lose a network connection on any computer on the network, a big FIX button usually does just that. Except in this case There's also a network map where you can interrogate each device and see what's going on. This confirmed what each wireless connected device had already told me; they were still part of the overall network, but not connected. A look at the log however gave a different story. Some cable connected devices that were logging in and out at random times, usually for only a second or two - the longest was seven minutes.

Now this was getting beyond my competence levels, but I prodded around the various network settings dialogue boxes on the connected computers and all, to my untrained eye, seemed OK. In reality, this was about as useful as opening the bonnet of your car when it breaks down and simply staring into the engine bay as if some holographic arrow is going to appear and point to the offending part.

I even tried logging into the modem and secondary router/ switch I'd added to get more connections, to run the wizards again. Now I knew (as I had read the manuals) that the modem was a 192.168.0.1 connection and the router/switch was a 10.1.1.0 one, but for the life of me, could not connect. It was time to use an atom bomb to crack a walnut.

I unplugged everything (after powering off) and connected the modem directly by cable to the Ferrari laptop. Now I could connect and check all the appropriate settings correctly. Nothing seemed terribly amiss to my untrained eye, and anyway, it had all been working before? The next task was to do the same for the router/ switcher. Again all seemed OK, but as I say, I have an untrained eye in this specific area. OK, we'll reconnect everything and see what happens. Nothing changed.

So, I'd done all the logical things, read all the manuals, tested and changed all the cables around, powered down and up... what was left?

IT Journalists have a closed discussion list on the internet where we variously chat, scold, swap ideas ask for contact names and so on. One of the least used areas is trouble shooting as many of these guys are girls are bucket loads of knowledge ahead of me (including PC Update regulars Adam Turner and Anthony Caruana). I had the answer within minutes, and it was so obvious.

For those that have followed so far, but are not technically savvy, let me explain. Each device on a network is issued a number called an IP address. The numbers I mentioned earlier (192.168.0.1 for example). This is unique to that device and allows other devices to communicate. This number is issued usually by the modem/ router and there is an option in the modem's setup to switch it on and off. You may recall I had added a second router/switch to give me some more ports and you guessed it, the default is "on" for that command. It is usually enable as a DHCP server.

Effectively, I had two devices issuing IP addresses to everything attached to the network! And of course as they were not the same (one was giving numbers in the 192.168.0.x range and the other the 10.1.1.x range), these poor devices had no idea what was going on. Once I turned that OFF in the secondary router/ switch all became good.

Now my homework for tonight, is to work out why it only affected the wireless based devices ... and to write in Notepad 1000 times, "ask your peers first", "ask your peers first".

Reprinted from the March 2009 issue of PC Update, the magazine of Melbourne PC User Group, Australia

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