Procedure: For the Windows version, run from the directory where the
executable is located. For Linux, compile and make the application
and execute with the syntax of:
ngrep
For Linux
From the directory containing the compressed files, type tar ??“zxvf ngrep-
1.40.1.tar.gz.
The compressed files will uncompress into a new directory named ngrep.
Change to the new directory by typing cd ngrep and pressing Enter.
The next step is to compile the application to the specific machine it is
installed on. This is done by typing ./configure.
214 Practical Hacking Techniques and Countermeasures
The ngrep application will now compile to the specific machine it is on.
The last step is to install the application by typing the make command.
Sniffing Traffic 215
The ngrep application will install.
To execute, type:
./ngrep
216 Practical Hacking Techniques and Countermeasures
The ngrep application will start. At this point ngrep will capture all traffic
to and from the computer it is installed on. To stop the capture hold down
the Ctrl key and press the C key.
*Note: Keep in mind that the traffic you see is completely dependent upon the
environment the computer ???sniffing??? resides in. For example, if the network
link you are using is connected to a network hub, you will be able to see all
traffic going through that hub to all other computers on that hub. If, however,
the network link you are using is connected to a switch, you will only be
able to see traffic specifically destined to/from your connection.
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