Bubulle's weblog

14 04 2008

Mon, 14 Apr 2008

IP over DNS for dummies

Once again, I'm sitting in an airport (CDG) and enjoying the benefits of IP over DNS to bypass the outraegous rates for wireless access (about 10 euros for 1h if that didn't change since last year).

Actually, having IP over DNS work is pretty simple. What you need is:

"Appropriate software" here is, IMHO, the iodine package in Debian. There's nothing as easy to setup as it is. There is no package for etch, AFAIK, but backporting it is straightforward.

You then need to create an entry in your foo.bar domain, such as "tunnel.foo.bar" and have it point to your static address.

Then you run iodine on that server, listening to port 53 (with a configured password). That creates a virtual interfaces with something like 10.0.0.1 as address.

When you need IP over DNS access with your roaming laptop, all you need is to connect to the expensive network, then launch iodine and provide it two parameters: the "tunnel.foo.bar" address and a local address (for instance 10.0.0.2). If everything works well, you'll be prompted for the password and voilà. You have a tunnel between your local 10.0.0.2 address and the remote 10.0.0.1.

The rest is a matter of network routing and you can now access the entire Internet through your remote server with no charge. The entire traffic goes through DNS requests to the local DNS server. That can be fairly slow but all a geek needs is receiving/sending mail and remote SSH access, right?

This doesn't work in every place, unfortunately. Many wireless providers block such traffic in some way. But, at least in Aéroports de Paris, I can promise that will work..:-)

posted at: 08:42 | path: /bubulle/planet-debian | permanent link to this entry

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