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Monthly Archives: February 2011

Firesheep, or, beware the passwordless wireless network

I’m late to the party in writing about firesheep.  For those not into web security, it basically means that it has become easy peasy to grab someone’s credentials when they are surfing the web via a non encrypted wireless network–the kind that used to be at a few coffee shops but now are at laudromats and car repair shops.

The upshot: think long and hard about surfing any sites that you sign in to that doesn’t encrypt all traffic thereafter (I’m looking at you, Yahoo! Mail).  If you must, consider running blacksheep, change your password regularly, don’t have the website ‘remember you’, and make sure you sign out (which typically invalidates your cookies)–don’t just close the browser.

Jeff over at Coding Horror does a great job of explaining what the fundamental issues are as well as possible solutions, and I had a friend point out that you can extend firesheep with a bit of javascript.

Writing a munin plugin

Recently, we’ve run into some stability issues with our main web application.  It’s a small company, so even though I’m definitely not the ops guy, everyone is pitching in with ideas and suggestions.  One thing that the ops guy did install that has been super useful is munin.  This graphing software lets you monitor, over time, many different aspects of your web application and/or servers.  It has been invaluable in letting us know what the effects of the various changes we’ve made have been.

Questions that munin helps you answer can pretty impressive.  For example, does doubling the amount of memory available to your webapp container help stability?  How can you know unless you’re measuring stability?  What happens if you prohibit certain bots from visiting your website?  When during the day or week is your server running hottest?

We have a watchdog that monitors our main application server, and if it is not responsive, restarts it.  The watchdog also records when the restart occurred.  I decided, as a fun project, to write a plugin for munin that would graph the number of restarts per day, as a high level ‘are we more stable yet’ graph.

Writing a plugin was trivial–it’s a shell script that follows certain output formatting. All I really needed was this HOWTO and this explanation of the types of data sources, though the FAQ is, as per usual, worth a scan.

Munin is by no means perfect (my dream feature would be the ability to annotate graphs at a certain moment in time; ‘this is when we released version 2.1’), but it is a huge hammer in the IT toolbox for understanding current and historic behavior of your application.

Gratitude List

Every so often, I just need to stop and say thanks.

Thanks for my family and parents, providing all kinds of education when they raised me.

Thanks to my wife, for being patient and loving, even when I’m not my best.

Thanks to my past and current clients, colleagues and employers, for giving me amazing opportunities, challenging me and trusting me.

Thanks to the vast number of people who contribute to making the internet a fantastic place (this is a software blog, after all).  Whether you create content or build plumbing, the internet is richer for your contribution (even the guy behind lolcats, but especially stuff like this and this).

Every so often, I get wrapped up in some small drama, but nothing knocks me back on my heels and makes me say ‘Damn, I’m lucky’ like making a gratitude list, even one like this which is incomplete.

Say thanks–it feels good!