Linux

Writing An Ebtables Match Module Tutorial

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One of the biggest problems I have had when working with Linux and other open-source projects is the lack of up-to-date documentation. Some projects go to great lengths to modernize documentation and others don't at all which results in the project being forgotten. Netfilter Xtables modules while in use on almost every system, seem to not get the polish they deserve for tutorials, examples and updated documentation.

Bridge Silently Drops LLDP Traffic Despite Ebtables Rule

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I recently discovered that LLDP traffic is silently blocked/dropped via a mask in br_input.c and will not forward LLDP despite having a rule with the correct protocol value in ebtables. In ebtables, the packet count will not increment and no messages are generated in the kernel logs.

To fix the netmask value to allow LLDP, patch net/bridge/br_private.h or use my patch:

Explaining Sockets and Terrifying You With C

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One of the things any aspiring security professional or network admin should know is - what is exactly a socket and what do they do?. This is tutorial is a different approach that I have been toying with on how to best explain to beginning IT or security students who are just beginning, but have no experience using "low-level" languages like C. One of my esteemed professor's once said: "God intended us to program in C" and I believe that today's programmers should begin with a language which will teach them responsibility.

Bash Scripting - Recursive MD5sum On Files In Directory

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Recently, I wanted to get the MD5sums of all of the files with a specific extension in the current directory and create a hash sum file for each. This was achieved using the following Bash script.

#!/bin/sh

# Get a list of files in a directory without the .md5 extension
# Note the ticks
LIST=`find . -name "*.txt" -a ! -name '.md5'`

HP-Envy 14 Power Tweaks - Updated

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Battery life on my HP-envy is down right horrible in Linux - Fedora 16 by default results in only about two hours of operation before it shuts down (and is about 60c) when compared to the almost 5 hours of running time in Windows 7. Here are some tweaks to improve it to 5+ hrs with minor use and minimal wifi:

Prerequisite packages:

Install the following:

sudo yum install pm-utils tuned
sudo chkconfig tuned on

Install Jupiter and get it configured

Colored printf messages in Linux

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If you have ever wanted to have colored printf statements for easier debugging - look no further

printf("%c[%d;%dmColor Me!%c[%dm\n",27,1,33,27,0);

Starting with the parameter - 27, this initiates the coloring. The rest of the parameters are (attribute);(fore color);(background color).


Text attributes
0 All attributes off
1 Bold on
4 Underscore (on monochrome display adapter only)
5 Blink on
7 Reverse video on
8 Concealed on

Ministry of Sound Radio Station for Linux Rhythmbox

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I became a little tired of having a browser window open when listening to some of my favorite music so I gave Rhythmbox a shot.  This was a fresh install of Fedora 16 and needed some tunes.

Add Ministry of Sound to Rhythmbox

To add Ministry of Sound radio to your radio list, perform the following:

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