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Force DD-WRT to use OpenDNS Servers for DNS Queries

In one of my recent articles, I explained how I set-up a guest wireless network for our work place (after getting it to work with the right wireless channel :))

After configuring the guest access point, I set up the DNS servers to point to OpenDNS in order to provide a safer and faster DNS service (compared to the default DNS servers our ISP provides) as well as choosing what web-sites should be allowed on the network.
For example, bandwidth hogging (Media/Video Sharing) and other web-sites which could potentially be used for illicit purposes (P2P/File Sharing) are forbidden on the network.

However, without any firewall rules on the router itself, it would still be possible for a guest on the network to change their DNS settings on their wireless adapter to point to any other DNS server; effectively bypassing all OpenDNS filters on the network for that specific client.

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Using DD-WRT and DNS-O-Matic to Automatically Update DynDNS, OpenDNS and Other Services

DNS-O-Matic is a free service provided by OpenDNS. With DNS-O-Matic, you can propagate IP address changes across multiple services such as DynDNS, OpenDNS and many others.

With DD-WRT, you can set-up DNS-O-Matic so that your services stay updated with your IP changes as soon as they happen.

This article will very quickly go through the process of setting DNS-O-Matic on your DD-WRT powered router.

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Choosing the Right Channel for Your Wireless Network

Choosing the wireless channel to use on your network can be a real pain in the ass; especially if you live or work (if this is a business network) in a densely populated area.

Put simply, channels are the radio ‘frequencies’ which your devices use, to talk to the router to get on to the internet or on the LAN.
If there are too many routers using the same channel in a close proximity, you are more likely to experience a slower connection, connection dropouts, general interference and other problems.

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How StolenCameraFinder and EXIF Work

I found a unique website the other day called StolenCameraFinder – I lost my Sony A200 DSLR a while ago so I decided to give StolenCameraFinder a go to see what it could do for me.

In a nutshell, you upload a photo taken by the stolen/lost camera to the website. It then cross references a unique serial number which is found in the picture against a large database of serial numbers. If the serial number is found in the database, it could potentially mean that a photo was taken from your camera and uploaded online after it was lost/stolen.

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Installing TCPDump on DD-WRT WRT54GL

This article will serve as a quick tutorial on installing TCPDump on a LinkSys WRT54GL box running the custom DD-WRT firmware.

TCPDump is a command line packet analyser. It’s a bit like Wireshark except it is command line based and in this tutorial, we will be installing it on a router and not on a PC.

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