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Trainig for CCNA 640-802

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Q: What is the purpose of the Spanning Tree Protocol (STP)?
A: prevents Layer 2 loops

Q: What creates a loop-free path through a switch network?
A: Spanning Tree Protocol

Q: Which statement is true regarding states of the IEEE 802.1D Spanning Tree Protocol?
A: Ports listen and learn before going into the forwarding state.

Q: Which industry-wide specification was developed to decrease the time that is needed to move to the forwarding state by switch ports that are operating in a redundantly switched topology?
A: RSTP


Q: Refer to the exhibit. Which switch will be elected the root bridge and which switch will place a port in blocking mode?
A: SW4 will get a port blocked.
A: SW3 will become the root bridge.

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Create Nagios Icons

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Nagios

If you ever tried to make Nagios Status-Map a little nicer by adding some dependencies and some pretty icons, you have probably came across some little collections/packs of icons at NagiosExchange.
But if you need a special one, you must do it by yourself.
And you probably noticed that you need images with .gd2 extension
Here is how to convert a PNG image into .gd2 (GD Graphics Library format)

Solution one:

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aptitude install netpbm
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pngtopnm example.png | pnmtopng -transparent =rgb:00/00/00 2>/dev/null | pngtogd2 /proc/self/fd/0 example.gd2 0 1

Solution two:

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aptitude install libgd-tools
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pngtogd2 phone.png phone.gd2 0

Understanding FTP using commands

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FTP and SMTP are simple text based protocols, I show you how to get some files without a graphical FTP-Client.

Connect with Telnet:

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id@acer:~$ telnet debianuser.org 21
Connected to debianuser.org.
USER anonymous
PASS anonymous
PASV
RETR deli-0.8.0-core.iso

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Make your linux speaking

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Speaker

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echo 'you are a loser' | festival --tts
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for count in $(seq 1 10) ; do espeak "Go Away" ; done

Make speaker louder:

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amixer -c 0 sset Master,0 100%;
amixer set Master 100%
# or
amixer set PCM 100%

Another funny things:

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export DISPLAY=:0
xmessage 'YOU ARE BEING WATCHED. MUHAHAHAHahaha'

PHP Security

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PHP

PHP reveals its presence on the server in a variety of ways: It may send an HTTP header (X-Powered-By: PHP), or append its name and version to Apache’s signature. In addition, there are easter egg URLs that return the PHP logo or some PHP authors, one of them is:
http://www.host.com/index.php?=PHPB8B5F2A0-3C92-11d3-A3A9-4C7B08C10000

Obviously there is no reason to let end users know about the server’s PHP version. Luckily, there is a switch in php.ini that will disable all of the above:

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expose_php = Off