A Linux box serving as a network gateway needs two network interfaces: eth0: Connected to the local network (LAN) with IP 192.168.0.1 eth1: Connected to the upstream network (Internet) with IP 198.51.100.1 The goal is to allow clients on the 192.168.0.0/16 network to route traffic through this gateway to reach external networks. Enable IP Forwarding…
SELinux provides mandatory access controls that catch security violations most firewall and file permission rules miss. Before disabling it, exhaust other options — SELinux warnings often reveal real security problems worth understanding. That said, there are legitimate reasons to adjust SELinux: testing application behavior without policy violations, troubleshooting misbehaving software, or running systems where the…
Guake is a drop-down terminal emulator for GNOME that brings the Quake-style console experience to Linux desktops. When you press a hotkey (F12 by default), a terminal slides down from the top of the screen. Press it again and it retracts. It’s fast, minimal, and designed purely around keyboard efficiency. Installation On Fedora/RHEL-based systems: sudo…
A SOCKS5 proxy tunneled through SSH provides encrypted communication between your client and a remote server. This is useful for bypassing network restrictions, securing connections on untrusted networks, or routing traffic through a trusted server. Basic Setup The simplest approach uses SSH’s dynamic port forwarding with the -D flag: ssh -D 8080 username@sshd_server This creates…
Xen remains in production use across several platforms (AWS EC2, Citrix Hypervisor), though KVM has become the default hypervisor for most Linux distributions. This approach is most relevant if you’re managing legacy Xen infrastructure or working with providers that standardize on it. When managing multiple Xen DomU virtual machines with similar configurations, creating individual configuration…
Xen remains in production use (AWS EC2, Citrix Hypervisor), though KVM has become the standard Linux hypervisor. This guide covers automating backups for file-backed Xen virtual machines. The approach adapts to other hypervisors like KVM with minimal modification. Architecture and Prerequisites The backup system assumes: Virtual machines stored in /lhome/xen/ with individual directories per VM…
This post analyzes I/O performance between loopback and blktap backends for Xen file-backed virtual block devices (VBDs), based on testing from 2013. While Xen remains in production use (AWS EC2, Citrix Hypervisor), most Linux deployments now default to KVM. For modern virtualization needs, consider KVM/libvirt or container solutions like Docker and Kubernetes. This post is…
When you need to start long-running commands while continuing to work in the shell, run them in the background. Bash and other modern shells maintain a job list and allow you to switch jobs between foreground and background execution. Only one job can run in the foreground at a time. Starting a Background Job Append…
mpv inherits much of MPlayer’s command structure, but with modern improvements for hardware acceleration, Wayland support, and codec handling. Here’s how to configure default startup volume and playback position. Configuration File Edit ~/.config/mpv/mpv.conf and add your defaults: volume=80 start=10 The volume parameter sets initial volume as a percentage (0–100). The start parameter specifies playback start…
When using lftp to connect to FTP servers, you may encounter a stall with “Making data connection” after logging in: < — 227 Entering Passive Mode (xx,xx,xx,xx,xx,xx) —- Connecting data socket to (yy,yy,yy,yy) port zz `ls’ at 0 [Making data connection…] The connection hangs indefinitely, though other clients like FileZilla work fine on the same…
Accessing a remote desktop environment on a Linux server securely requires proper tunneling. While SSH X11 forwarding works for single applications, VNC provides a full graphical desktop session. By combining VNC with an SSH tunnel, you encrypt all traffic and can work around firewall restrictions that only allow port 22. Why VNC Over SSH? VNC…
MPlayer is largely unmaintained; mpv is the actively developed fork that handles 95% of these commands with compatible bindings. That said, if you’re still running MPlayer or need legacy support, here’s what you need to know. MPlayer uses a fully configurable keyboard control layer. Most of these shortcuts work in mpv as well, though some…
DNS caching helps reduce lookups but sometimes you need to clear it after DNS changes, certificate updates, or to troubleshoot resolution issues. Modern Linux with systemd-resolved Most contemporary Linux distributions use systemd-resolved as the default DNS resolver. Flush the cache with: sudo systemctl restart systemd-resolved Or use the resolvectl command: sudo resolvectl flush-caches To verify…
Xen remains in active production use—particularly in cloud infrastructure like AWS EC2 and Citrix Hypervisor—though KVM has become the standard hypervisor for most Linux distributions. If you’re managing legacy Xen deployments, this guide covers the essential steps for cloning VBD-based DomU instances. Prerequisites Before starting, ensure: The source VM is powered off (critical to avoid…
This article documents performance benchmarks for Xen virtualization, comparing CPU and memory performance between Dom0 (privileged domain), DomU (unprivileged guest), and bare metal. While Xen remains in production use (AWS EC2, Citrix Hypervisor, Oracle Cloud), most Linux distributions default to KVM for new deployments. For contemporary virtualization needs, evaluate both Xen and KVM based on…
Desktop clients for WordPress have largely fallen out of favor in recent years, but they still serve a niche purpose for users who prefer offline writing and batch publishing. Lekhonee was one such tool — a GNOME-based WordPress client that provided a lightweight alternative to the web interface. Important context: Lekhonee is no longer actively…
MPlayer is largely unmaintained; mpv is the actively developed fork that replaced it. Most MPlayer subtitle commands work in mpv with minor syntax adjustments. This guide covers both. External Subtitle Files Handling Character Encoding Chinese subtitle files often display as garbage when the player guesses the encoding wrong. Specify the correct codepage explicitly. For an…
Keeping Thunderbird running constantly makes sense for monitoring incoming mail, but leaving it on the taskbar consumes screen real estate. System tray integration is cleaner—minimize to a small icon and optionally display unread message counts. Thunderbird’s addon ecosystem provides platform-specific solutions for this. Note that addon availability and compatibility can vary; check the Mozilla Addons…
When you open a Windows file in Vim (or Neovim), you’ll often see ^M characters at the end of lines. These are carriage returns (\r) from Windows line endings (CRLF), which don’t display properly on Unix-like systems that expect LF-only line endings. Quick Fix The fastest way to remove these characters is with a substitution…
Fedora 中文字体的显示一直是个常见问题，特别是在英文环境中。通过合理的字体配置，可以获得清晰舒适的中文显示效果。本文介绍的方案使用开源字体，这些字体在 Fedora 的标准仓库中都可以获得。 快速配置 如果你只想快速完成配置，运行以下命令： sudo dnf install cjkuni-ukai-fonts cjkuni-uming-fonts sudo wget https://raw.githubusercontent.com/zma/config_files/master/others/local.conf \ -O /etc/fonts/local.conf 这会安装文鼎楷体和文鼎明体，并配置字体渲染优先级。注销后重新登录即可生效。 推荐字体包 Fedora 仓库中提供了多个中文字体包： 基础中文字体： # 文鼎明体 — 适合正文阅读，清晰度高 sudo dnf install cjkuni-uming-fonts # 文鼎楷体 — 适合标题和打印 sudo dnf install cjkuni-ukai-fonts Google Noto 字体（推荐）： # Noto Sans CJK — 现代、清晰、覆盖全面 sudo dnf install google-noto-sans-cjk-fonts # Noto Serif CJK…