ns-2 reached end-of-life in 2011 and is no longer maintained. If you’re looking to simulate network behavior, you should use ns-3 instead, which is actively developed and provides significantly better accuracy and modern tooling. Why ns-3 Over ns-2 ns-2 was influential in academic networking research, but its architecture has fundamental limitations that became apparent over…
Every user working with Git needs an SSH key pair for authentication. Generate one if you don’t have it: ssh-keygen -t ed25519 -C “your-email@example.com” Ed25519 keys are preferred over RSA for better security and performance. The command creates ~/.ssh/id_ed25519 (private key) and ~/.ssh/id_ed25519.pub (public key). Share the public key with your Git server administrator to…
Thunderbird’s built-in compose window is functional but limited. Using Vim as an external editor gives you the full power of modal editing and your customizations for email composition. Prerequisites You need Thunderbird with the External Editor extension installed. As of 2026, this extension continues to work with current Thunderbird versions. Install it from the Thunderbird…
Flash Player reached end-of-life on December 31, 2020, and modern browsers no longer support it. However, if you’re working with legacy systems, archived content, or old web applications that still require Flash, here’s what you need to know about the historical setup and modern alternatives. The Original Setup (Historical Reference) On 64-bit Linux with Firefox,…
IPv6 is enabled by default on most Linux distributions. While IPv6adoption has grown, many environments still rely primarily on IPv4, and disabling IPv6 can simplify networking configurations or resolve compatibility issues. Quick Method: Disable via modprobe The most straightforward approach is to prevent the IPv6 kernel module from loading: echo “options ipv6 disable=1” >> /etc/modprobe.d/disable-ipv6.conf…
MPlayer reached end-of-life years ago. Its active fork, mpv, maintains all screenshot functionality with identical or simpler syntax. This guide covers mpv, which handles both single captures and burst sequences. Enable Screenshot Support Screenshot support is built into mpv by default — no filter loading required. However, you can customize behavior by adding configuration to…
Running 32-bit Firefox on a 64-bit Linux system is less common than it used to be, but there are still valid reasons: testing web compatibility across architectures, supporting legacy plugins, or working with older systems. This guide covers Fedora and RHEL-based systems, though the core approach applies to other distributions. Prerequisites Ensure you have multilib…
Mistakes happen during development. Git provides several commands to undo changes at different stages—before committing, after committing, or in specific files. Understanding which tool to use depends on where you are in the workflow. Revert the entire working tree before committing If you’ve made changes to multiple files and want to discard everything back to…
The uptime command is the quickest way to check how long your system has been running: $ uptime 22:19:29 up 10 days, 22:26, 5 users, load average: 0.00, 0.00, 0.01 This output shows: Current time: 22:19:29 System running for: 10 days, 22 hours, 26 minutes Active user sessions: 5 Load averages: 1-minute, 5-minute, and 15-minute…
Connecting servers with internal IPs across multiple clusters over the internet is a common infrastructure requirement. While a traditional VPN is the standard approach, you can implement similar functionality using iptables and Network Address Translation (NAT) rules, often with lower overhead than VPN solutions. This method works by forwarding traffic between clusters at the IP…
Fedora’s default font rendering can look subpar, particularly on laptops with standard LCD screens. TrueType bytecode interpreter (BCI) support significantly improves rendering quality, but licensing restrictions have kept it disabled in Fedora’s default FreeType builds. The TrueType bytecode patents expired years ago, so BCI is now safe to enable. While FreeType 2.13+ ships with BCI…
LVM (Logical Volume Manager) lets you combine multiple physical disks into flexible storage pools. This guide covers creating a volume group from multiple disk partitions—a common setup for servers that need flexible storage allocation across Xen guests, databases, or other demanding workloads. Prerequisites This assumes you have two or more unformatted disk devices available. In…
LVM snapshots provide an efficient way to duplicate virtual machines in seconds rather than minutes. Instead of copying an entire filesystem, snapshots leverage copy-on-write semantics—physical blocks are only duplicated when the source or snapshot is modified. This approach works well for any LVM-backed virtualization platform, though Xen is used here as an example. Note: Xen…
LVM snapshots provide a fast, efficient way to duplicate virtual machines across servers. This technique applies to any LVM-backed hypervisor including Xen, KVM, and Proxmox. The process uses LVM snapshots on the source server, then transfers the snapshot image to the destination using standard Unix tools. Scenario Source server: 10.0.0.10 with VM stored in /dev/vg_xen/vm-10.0.0.123…
Building and maintaining Linux clusters requires coordinated management of user accounts, storage, networking, and services across multiple machines. This guide covers practical approaches to common clustering challenges, from unified authentication to network isolation. Account and Storage Management Unified Authentication and Home Directories Centralizing user management across cluster nodes eliminates the overhead of maintaining individual user…
The firmware (BIOS/UEFI) on your system contains critical hardware settings and boot information. Knowing your firmware version is essential for updates, compatibility checks, and troubleshooting. Here’s how to find it. Using dmidecode dmidecode is the standard tool for reading the Desktop Management Interface (DMI) table, which stores hardware and firmware metadata. Most distributions include it,…
A Fedora Live USB lets you boot directly into a Fedora environment without modifying your hard drive. You can use it to test Fedora, troubleshoot your system, or perform a fresh installation. This guide covers modern tools and workflows for creating bootable USB media. Back up any data on your USB stick first — the…
Xen remains a production-grade hypervisor used in enterprise environments (AWS EC2, Citrix Hypervisor), though KVM has become the default for most Linux distributions. This guide covers building a stable Xen Dom0 on current Fedora releases using modern kernel sources. Hardware Considerations This guide assumes server-class hardware with: Intel or AMD processor with virtualization extensions (VT-x…
Xen remains a critical hypervisor in production environments—AWS EC2, Citrix Hypervisor, and other cloud platforms rely on it—but most Linux distributions now default to KVM for general-purpose virtualization. If you’re working with Xen specifically, this guide covers Dom0 and DomU setup on modern distributions. When to Use Xen Xen is worth considering if you need:…
To find all available versions of a package in your repository, use the –showduplicates flag: dnf list –showduplicates kernel Or for other packages: dnf list –showduplicates <package-name> The output shows both installed and available versions with their release tags. For example: Installed Packages kernel.x86_64 6.8.1-1.fc39 @updates Available Packages kernel.x86_64 6.7.12-200.fc39 updates kernel.x86_64 6.6.25-1.fc39 updates kernel.x86_64…