Luis Sequeira
Luis Sequeira is an IT professional with experience in cloud environments, quality of service and network traffic analysis, who loves looking for solutions to engineering challenges, share knowledge. At work, the main challenge is to integrate different network and software technologies to provide solution in a wide range of areas, e.g., virtual network functions, machine learning, autonomous driving, robotics and augmented reality.
Before starting with the use of some Linux commands, I want to remind the importance of reviewing the reference manual for each command, because this is the place where you can find all the possible options. The reference manual can be displayed on a terminal using the "man" command, for example, if we see the manual of the "man" command in a terminal, we should write "man man" and we would see something like this:
Figure # 1: Linux terminal displaying the manual of the man command.
The 2 best tools for the capture and the interpretation of network data
02 December 2013
I present you my favorite applications to capture packets on the network, although they are well known for their features, I decided to give a little space to discuss some of their features. In addition to data capture, these applications are useful for certain packets analysis with the obtained data, on the other hand, when the analysis that we need to do is a bit complex or very specific, it is always advisable to build our own scripts, but there is no doubt that no matter for what we use them, this applications will help us to obtain useful network information. This applicacions can also be combined with traffic generators in order to analyze some network issues.
TCPDUM
TCPDUMP [1] is a tool for capturing traffic flowing through the network in real time, this includes packets transmitted and received on a specific network interface. This tool has no graphical interface, this makes for one of the favorite applications when you want to use minimum resources as possible, also be suitable for unattended packet capture, because it can be managed by command line as it can seen in Figure # 1.
Figure # 1: View of the contents of various packets for command line using TCPDUMP.
For some time I have been using various traffic generators, and today I want to share 3 of the that I most use for their interesting features. The traffic generators are useful for injecting traffic of certain applications or network services and not have the need to run such applications, in my case I used to generate the traffic of VoIP, video streaming, video surveillance, and even to make some reverse engineering on certain commercial devices. Then I leave a short review of each of them: