Xaprb

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Archive for the ‘networking’ tag

How to set up host interface networking for VirtualBox on Ubuntu

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VirtualBox is really nice, but if you’re like me, maybe you found the networking confusing. There are three ways to do it, as explained by the manual, and the best way is with host interfaces, which don’t have limitations like the inability to ping and so on. I found what I think is a pretty good way to set up host interface networking.

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Written by Xaprb

November 5th, 2008 at 11:26 pm

The unexpected consequences of SELinux

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I’ve been working with a client recently who has SELinux on his servers.  It has been quite a struggle sometimes.

My colleages tell me that SELinux has a pretty noticeable performance impact.  I am not sure if we have benchmarks to support this; at any rate, the client said it’s OK, we’ll take the performance hit.

There have been a few problems (Nagios can’t run because it can’t write to its own pid file, etc etc).  Last night there was something new: “too many connections” when trying to connect to MySQL.  As a result the site was down, and it wasn’t possible to log in to MySQL and see why. But the oddest thing happened: mysqld would not shut down.  It was sitting basically idle, doing absolutely nothing, and wouldn’t stop. There was nothing in any log files to show what might be going on.

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Written by Xaprb

October 16th, 2008 at 8:43 am

Ubuntu on Dell Inspiron 1501

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I recently bought a Dell Inspiron 1501, which I got a great deal on thanks to the fine people at DealNews. The base system was $449 shipped, and I chose to upgrade the processor to dual AMD64s. But I didn’t buy the system that came with Ubuntu pre-installed; for whatever reason, the one that came with Windows offered a special discount (normally the Windows tax for otherwise identical machines appears to be around $150, and I’m certainly not going to run Windows).

Therefore, I was not sure Ubuntu would support all the hardware. It’s the same story it’s been for as long as I’ve been using computers: hardware manufacturers withhold specifications from the Free Software world, so there is always a chance something will be a trouble. The good news is, I’ve only noticed two very minor incompatibilities out of the box.

One is that the Fn+arrow keys won’t change my screen brightness, at least under XFCE. Strangely, my ancient Dell laptop had no trouble with that. I assume the old one was a hardware-controlled feature and this one needs some software support, but I could be wrong.

The other thing is the built-in wireless card, which isn’t supported with Ubuntu 7.04′s drivers out of the box. However, I quickly found a set of drivers for the Broadcom Corporation Dell Wireless 1390 card, and was up and running shortly thereafter. The only thing I had to do after installing the drivers was press the Fn+F2 key, which turns the card on.

Otherwise everything works brilliantly.

And now for a rant: click through to that page about the drivers, and you’ll see an example of what I consider the Ubuntu sudo disease. There’s even a screenshot of someone typing sudo uname -a and using sudo to remove a file he didn’t create with sudo. I think unfortunately, Ubuntu’s policy of allowing one to run any command with sudo has created a crop of people who don’t understand what should and shouldn’t be privileged; some of them seem to believe that ‘sudo’ is what you type at the beginning of every command. It completely defeats the purpose and circumvents the security gained by not running as root. For my part, when I want to administer my system, I become root, do what I need to do, and then quit again. I rarely sudo any command other than sudo su -.

But that’s just me.

Written by Xaprb

July 24th, 2007 at 8:48 pm

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