Category Archives: Info

Bernstein’s comment about third-party DNS and the reality with qmail

In a document written a couple years ago, Dan Bernstein describes the costs and benefits of third-party DNS services.

In his document, he states that:

“Third-party DNS means the difference between email being requeued and email bouncing.” No, it doesn’t. Mail transfer agents defer delivery attempts when DNS servers are unreachable, just as they defer delivery attempts when SMTP servers are unreachable.

This is simply not true.

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Hard drive woes

Yesterday at around 16:30 the secondary hard drive on my decade old linux router passed away. Most of the software continued working, only the DNS server stopped working. Not knowing what was going on, I restarted it, and it's not starting anymore… :-( I don't believe in esotericism, but I guess I had a premonition last week-end when I bought a Soekris net4501 that I should be receiving in a day or two. So for those who are emailing me, it might take me a bit more time to answer, since my mail server was behind that router. You can reach me at [email protected] in the meantime. Update 20070619 19:57: I managed to use a Linksys wireless router running DD-WRT as the new router. It's not as good as my old one, but it will do until I can set up the Soekris board. Update 20070622: The Soekris board is now set up with m0n0wall with openvpn support. It's a bit more rigid than I had hoped for, but at least it's really easy to set up.

The rsync algorithm applied to S3

Many people would like to see rsync work with S3, unfortunately S3 is a “dumb” file storage that can’t run rsync. It’s possible to run rsync on a EC2 that accesses your files on S3, but it’s complex, (more) expensive and not elegant.
I spent some time reading the rsync algorithm and seeing how it could be adapted to S3 (or any other dumb file storage like a FTP server).

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Bad file descriptor on perl and IIS 6 (Win2003)

Here’s a sticky problem that took me quite a while to find out.
I had a perl script that did a qx(something.bat $file); it worked fine on Win2000/IIS5, it worked fine on the command line on Win2003, but on the web site, I would always get a Bad file descriptor error.
So I replaced qx by system, and then I got the error: Can't spawn cmd.exe Then it was easy to figure out that the problem was related to cmd.exe.
The problem was that the IUSR_WEB user did not had the Read/Execute permissions on C:\windows\system32\cmd.exe. Also be sure to put $ENV{'PATH'} = 'C:/windows/system32/;'; on top of your script.
So in case anyone has this problem in the future, that’s the way to solve it.

Is this the way to Armadillo?

Des petites histoires de l’autre coté de la grande flaque:
En 1971, un crooner du nom de Tony Christie a sortie une toune s’intitulant “Is This The Way To Amarillo?” Amarillo est une petit ville du Texas. C’était une parodie qui faisait semblant de faire la promotion touristique de ce petit bled texan.

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My servers

For your inner nerd who wants to know what is under the hood of my servers, here's the place to look.

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Software defined radio

I just read that a Universal Software Radio Peripheral (USRP) has now gone into production. The unit is priced at $450 for the motherboard and about $50 for daughterboards (see the links below for more infos about mother/daughter boards). It’s still quite expensive, but considering that the next cheapest one costs tens of thousands of dollars, this one is pretty attractive. Maybe the next version will cost around 100$ and everyone will want one (or two).

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Caméras du MTQ

J’habite à Beaumont et je travaille à Sainte-Foy, je dois donc faire le trajet sur l’autoroute 20 de Beaumont aux ponts deux fois par jour. J’ai souvent recourt aux caméras de circulation du Ministère des transports du Québec (MTQ) pour connaitre les conditions routières sur ce tronçon. J’ai créé une interface plus simple et plus rapide pour voir les images de ces caméras.


J’ai trouvé cette feuille [168 Ko] dans un tiroir, j’ai recopié les données si ça peut intéresser quelqu’un.

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