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Archive for the ‘System Administration’ Category

nginx: Blocking Access to /xmlrpc.php

I recently ran into an issue on a WordPress site running behind an nginx web server. The site was frequently being attacked by a botnet hitting /xmlrpc.php so rapidly, it would eventually force the FastCGI processes behind nginx to consume all available CPU. Naturally, this would cause all legitimate traffic to the site to timeout. […]

Categories: System Administration

Goodbye, discoveryd. Hello again, mDNSResponder.

Great! Once again, Apple has made a change in how DNS is handled in Mac OS X. Originally, Yosemite (10.10) had replaced mDNSResponder with discoveryd. This meant that all of those who had made a change to force mDNSResponder to always append search domains to DNS lookups had to make a new change to accommodate […]

Categories: System Administration

Why Isn't tmpreaper Working?

If you have a directory that you want to keep clean, tmpreaper is a great way to remove files based on how old they are. The other day, I had a directory that looked like this: x@x:~/dump$ ls -l -rw-r--r-- 1 x x 212268169 Mar 15 01:02 x-2015-03-15.sql.gz -rw-r--r-- 1 x x 212270156 Mar 16 […]

Categories: System Administration

WARNING: The following packages cannot be authenticated!

We run several (read: hundreds) of servers that are still running Debian 6 (Squeeze). A few months ago, we started seeing the following errors coming from the daily apt cronjob: 'WARNING: The following packages cannot be authenticated!'

Categories: System Administration

OS X Not Appending Search Domains - Yosemite Edition

It seems this problem has resurfaced again with the new version of Mac OS X. More specifically, this problem seems to affect appending search domains when the hostname contains a dot. In Yosemite (10.10), mDNSResponder has been replaced with discoveryd. Fortunately, all we need to do here is add the --AlwaysAppendSearchDomains argument to the LaunchDaemon […]

Categories: System Administration