Security

Are you running into the ERR_SSL_VERSION_OR_CIPHER_MISMATCH error? This error happens in a user’s browser when they try to access a website. It means that there’s a difference between the security information that was provided and the actual configuration of the website. This guide provides solutions.

Nmap stands for Network Mapper. It is an open source tool for network exploration and security auditing. With NMAP, server administrators can easily reveal hosts and services on a computer, scan for security issues and check for open ports. The NMAP command line tool can audit and discover local and remote open ports, as well as network information and hosts. Here are some of the most useful Nmap commands with examples.

There are many different tools for monitoring network traffic on a Linux server. Each option has its strengths and weaknesses. Most of the command-line utilities are designed to be lightweight, so they do not inflate bandwidth reports. Some are designed to present a basic overview, while others provide detailed data. This guide offers the best Linux network monitoring tools.

If you do not keep your Ubuntu operating system up-to-date, you run the risk of compromising overall system security. Managing the process manually, wastes valuable resources and can even lead to overlooking essential security updates. In this tutorial, we explain how to Enable automatic security updates in Ubuntu 18.04. Doing so ensures your system stays protected with the latest security packages at all times.

The chown command changes user ownership of a file, directory, or link in Linux. Every file is associated with an owning user or group in Linux. Make sure to configure file and folder permissions properly. This tutorial will show you how to execute the Linux chown command to control who can modify file contents.

SELinux is a mandatory access control (MAC) enforcer built into the Linux kernel. It limits the privileges of individual services whose vulnerabilities might be a threat to the system. SELinux acts as a system-wide protective agent by enforcing security policies. CentOS systems without SELinux rely on the configuration of all its privileged software applications. A single misconfiguration may compromise the entire system. In this guide, you will learn how to check SELinux status and disable the service on CentOS 7.

When establishing a remote connection between a client and a server, a primary concern is ensuring a secure connection. For Linux users, the best practice of accessing and managing your server remotely is through the cryptographic protocol known as Secure Shell (SSH). Tutorial on how to Enable, Install, and Configure SSH on Ubuntu. Enabling SSH allows you to connect remotely to your server securely.

Sudo stands for superuser do. Sudo is a command used in Unix-like systems to allow a regular user to execute a program as another user. In most cases, it is the root user. Sudo gives you administrator-level permissions to run programs on your machine. This guide will show you how to create a user with sudo privileges on Debian and test the sudo access.

If a Linux process becomes unresponsive or is consuming too many resources, you may need to kill it. Most processes have their own methods of shutting down. Unfortunately, sometimes processes can malfunction and not allow themselves to be shut down. If a process is currently unresponsive, it becomes necessary to shut it down through the command line. View our complete guide on how to kill a Linux process using the command line.

Are you looking to change the root password in Ubuntu? Changing passwords is a good practice and should be done periodically. Linux allows multiple user accounts, each having its own password. Users can only change their own password. However, there is always a sudo/root (SuperUser) account. Root users can change the password of any account, including their own.