Category Archives: Sysadmin

what’s going on with the .org nameservers?

Posted on January 21, 2009 by ward

I got rather strange error messages from two servers this evening, one at 18:00:21 EST, and another one at 18:34:01 EST. One server lives in Brussels, the other in Boston. On both servers a (totally different) script executed via cron … Continue reading →

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lessons learned from a colo migration

Posted on October 2, 2008 by ward

I moved a bunch of servers from one colocation facility to another last night. I had been preparing this move for a few weeks. While everything went well in the end, things took much longer than anticipated. Here are a … Continue reading →

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of how XFS saved the day

Posted on March 15, 2008 by ward

Io, one of my mailservers, is a Xen instance. It’s moderately busy – a normal day sees about 12000 accepted messages and about 24000 rejected delivery attempts (spam). It’s an Exim/clamav/dspam setup, and a significant proportion of the 12000 accepted … Continue reading →

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wireless mac address cloning on WRT54GL

Posted on February 27, 2008 by ward

I have a bunch of WRT54GL units that still run OpenWRT Kamikaze 7.07 (latest version is 7.09). I needed to swap out a unit that is one half of a WDS pair, but preferred not to touch the other half. … Continue reading →

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xen 3.2 serial

Posted on February 18, 2008 by ward

Getting access to the serial port in a Xen 3.2 dom0 is somewhat complicated. This is the magic incantation for your grub menu.lst file to get console at 115200 bps on the first physical serial port, as well as on … Continue reading →

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sanitizing /var/log

Posted on February 13, 2008 by ward

I don’t know about you, but I like to have my system logs split day by day, particularly on busy machines. I also like to have a full timestamp (including year and timezone thank you) in system log files. The … Continue reading →

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testing smtp auth from the command line

Posted on November 2, 2007 by ward

Testing smtp auth can be a bit of a pain sometimes, particularly if SSL or TLS is involved. Mail clients often don’t really show what they are doing and/or don’t allow you to set all variables, like which authentication mechanism … Continue reading →

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a new record

Posted on April 19, 2007 by ward

This morning, a user on one of our machines (inadvertently) created a mail loop with a bad procmail script: 09:42:05 up 120 days, 9:23, 20 users, load average: 3367.40, 3265.08, 2751.75 I had seen machines go up to about 200 … Continue reading →

Posted in Free Software/Open Source, Sysadmin, Xen | Leave a comment

ECN

Posted on January 20, 2007 by ward

Explicit Congestion Notification (ECN, RFC 3168) has been around for quite a while now, but there are still lots of devices and hosts out there that don’t support it properly. For instance, http://www.npr.org, and apparently all HP’s ILO and ILO2 … Continue reading →

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MIT’s got a bit of bandwidth

Posted on January 19, 2007 by ward

Interesting interview with Jeff Schiller, MIT’s main network guy, in Network World. MIT is going to activate a direct link to New York city later this month – 72 10G waves. Yes. That’s 720Gbit/s. From Boston. To New York.

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