Linux Firewall

A virtual wall in the security system world is designed to protect our system from unwanted traffic and unauthorized access to our system. The security system in Linux OS is known as Linux Firewall, which monitors and governs the network traffic (outbound/inbound connections). It can be used to block access to different IP addresses, Specific subnets, ports (virtual points where network connections begin and end), and services.

We have a daemon’s name called Firewalld which is used to maintain the firewall policies. A dynamically managed firewall tool in a Linux system is known as Firewalld, it can be updated in real-time if there are any changes in the network environment.

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Getting hash of a file using CMD

A cryptographic hash is a fixed size string (or text) that is used as an identifier/fingerprint of some data. These are particularly useful in determining the integrity of files after they are transferred over a communication channel. Hashes are even utilized by certain OS-level processes for their working.

The command processor of Windows OS (cmd.exe) provides the user with the ability to compute hashes on files/Directories via an utility command named Certutil.

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Assoc cmd command

Assoc is command (internal) found inside Windows Command Processor Command Prompt, that allows for file extension to file type association. A file extension is generally last few characters in File Name after period (“.”). Though it is not mandatory for file to have an extension at all (in case of extension-less files).

Extension to file type association is enforced predominantly by Windows OS. Other Operating Systems such as Linux and macOS does support such association but don’t enforce them to levels of Windows. Linux Kernel rather utilizes Magic Numbers for recognition of file types. In this article, we will take look at assoc command found in cmd, and would look at uses of it.

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