How to limit network bandwidth on Linux

If you often run multiple networking applications on your Linux desktop, or share bandwidth among multiple computers at home, you will want to have a better control over bandwidth usage. Otherwise, when you are downloading a big file with a downloader, your interactive SSH session may become sluggish to the point where it’s unusable. Or […]
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How to make a file immutable on Linux

Suppose you want to write-protect some important files on Linux, so that they cannot be deleted or tampered with by accident or otherwise. In other cases, you may want to prevent certain configuration files from being overwritten automatically by software. While changing their ownership or permission bits on the files by using chown or chmod […]
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What are useful command-line network monitors on Linux

Network monitoring is a critical IT function for businesses of all sizes. The goal of network monitoring can vary. For example, the monitoring activity can be part of long-term network provisioning, security protection, performance troubleshooting, network usage accounting, and so on. Depending on its goal, network monitoring is done in many different ways, such as […]
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How to configure fail2ban to protect Apache HTTP server

An Apache HTTP server in production environments can be under attack in various different ways. Attackers may attempt to gain access to unauthorized or forbidden directories by using brute-force attacks or executing evil scripts. Some malicious bots may scan your websites for any security vulnerability, or collect email addresses or web forms to send spams […]
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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 speed up a WordPress website with Amazon AWS CDN

If your WordPress-powered personal blog or website is loading slowly, you are hardly alone. Rather than simply bemoaning your web hosting, you can take more proactive approaches to solve the problem, such as optimizing underlying web server stack (e.g., PageSpeed), tweaking content (e.g., minification), or even switching to a different publishing platform (e.g., Ghost or […]
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What is a good free control panel for VPS

Anyone with a reasonable level of Linux skills knows that no control panel can beat the plain-old command line interface for managing a virtual private server (VPS). One can still argue that there is a place for a good server control panel though, due to the streamlined interface for getting routine administration tasks done easily […]
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How to create dialog boxes in an interactive shell script

When you install new software in the terminal environment, you may often see informative dialog boxes popping up, accepting your input. The type of dialog boxes ranges from simple yes/no dialog to input box, password box, checklist, menu, and so on. The advantage of using such user-friendly dialog boxes is obvious as they can guide […]
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How to visualize memory usage on Linux

Lack of sufficient physical memory can significantly hamper the performance of Linux desktop and server environments. When your desktop is sluggish, one of the first things to do is to free up RAMs. Memory usage is even more critical in multi-user shared hosting or mission-critical server environments, where different users or application threads constantly compete […]
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