How to filter, split or merge pcap files on Linux

If you are a network admin who is involved in testing an intrusion detection system or network access control policy, you may often rely on offline analysis using collected packet dumps. When it comes to storing packet dumps, libpcap’s packet dump format (pcap format) is the most widely used by many open-source packet sniffing and […]
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How to block unwanted IP addresses on Linux efficiently

You may want to block IP addresses on your Linux box under various circumstances. For example, as an end user you may want to protect yourself from known spyware or tracker IP addresses. Or when you are running P2P software, you may want to filter out connections from networks associated with anti-P2P activity. If you […]
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How to configure a syslog server with rsyslog on Linux

A syslog server represents a central log monitoring point on a network, to which all kinds of devices including Linux or Windows servers, routers, switches or any other hosts can send their logs over network. By setting up a syslog server, you can filter and consolidate logs from different hosts and devices into a single […]
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How to install LAMP stack (Apache, MariaDB/MySQL and PHP) on CentOS

LAMP stack is a popular server-side software stack which is used to build and run dynamic web sites and web applications on Linux platforms. The LAMP stack is composed of Apache (as an HTTP server), MariaDB or MySQL (as a database backend), and PHP, Perl or Python (as a server-side programming language), and hence the […]
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How to run SQL queries against Apache log files on Linux

One of the distinguishing features of Linux is that, under normal circumstances, you should be able to know what is happening and has happened on your system by analyzing one or more system logs. Indeed, system logs are the first resource a system administrator tends to look to while troubleshooting system or application issues. In […]
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How to install LEMP stack (nginx, MariaDB/MySQL and PHP) on CentOS

The LEMP stack is an increasingly popular web service stack, powering mission-critical web services in many production environments. As the name implies, the LEMP stack is composed of Linux, nginx, MariaDB/MySQL and PHP. nginx is a high performance and lightweight replacement of slow and hard-to-scale Apache HTTP server used in the traditional LAMP stack. MariaDB […]
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How to download an ISO image with BitTorrent fast and safely from the command line

If you are one of those guys who have urge to try out every new (or even beta) release of Linux distribution to satisfy your curiosity and stay up-to-date, you will need to deal with the hassle of downloading big ISO images every now and then. ISO providers typically put up .torrent file of their […]
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How to turn your CentOS box into a BGP router using Quagga

In a previous tutorial, I described how we can easily turn a Linux box into a fully-fledged OPSF router using Quagga, an open source routing software suite. In this tutorial, I will focus on converting a Linux box into a BGP router, again using Quagga, and demonstrate how to set up BGP peering with other […]
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How to create and use Python CGI scripts

Have you ever wanted to create a webpage or process user input from a web-based form using Python? These tasks can be accomplished through the use of Python CGI (Common Gateway Interface) scripts with an Apache web server. CGI scripts are called by a web server when a user requests a particular URL or interacts […]
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How to monitor and troubleshoot a Linux server using sysdig

What is the first thing that comes to mind when you need to track system calls made and received by a process? You’ll probably think of strace, and you are right. What tool would you use to monitor raw network traffic from the command line? If you thought about tcpdump, you made an excellent choice […]
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