Disable BIND9 Recursive DNS Queries to Prevent UDP DDOS Flood Attacks

Sunday, January 12th, 2014

Turn Off BIND9 Recursion

By default, BIND9 is configured to allow recursive DNS queries.  This allows others to use your DNS server to query other domains on your server's behalf.  Unfortunately, recursive DNS queries can be used to amplify a UDP flood DDOS attack.  As such, for a shared web hosting environment, it is best to disable recursive DNS queries.  You can disable BIND9 recursion easily by running the following script:

cd ~/Downloads
wget -N "http://dinofly.com/files/linux/disable_bind9_recursion.tar.gz"
tar -zxvf disable_bind9_recursion.tar.gz
sudo bash disable_bind9_recursion.sh

It should work on all versions of Linux but has been tested and works perfectly on Ubuntu.  You may need to change the path used for the BIND config file. 

Keep Num Lock On at Startup on Windows Computers

Thursday, March 29th, 2012

Windows XP, Vista, and Windows 7 :: Keep Num Lock On at Startup

Despite what Microsoft claims, I've seen some computers not revert back to their last set num lock setting when Windows was last shut down.  Granted, this could be caused by Enterprise configurations.Here's a simple batch file that should keep Num Lock always ON when a user logs in.  It may or may not need to be run with administrator privileges based on your enterprise configuration.  I've had several users complain about the fact that Num Lock is turned off when they turn on their computers in the morning.  As a result, this batch file allows you to enable the setting that keeps num lock enabled after a user logs in with minimal effort.  I'm still under the impression that this is more work than the user simply pressing the num lock key to turn it back on.

REGEDIT4
@ECHO OFF
CLS
REGEDIT.EXE /S "%~f0"
EXIT

[HKEY_CURRENT_USER\Control Panel\Keyboard\]
"InitialKeyboardIndicators"="2"