Linux Server Admin with Fexingo: Sysadmin, Bash, and Server Engineering

In this episode, Lucas and Luna dive into the most common attack vector on Linux servers: SSH brute force. They explain how Fail2ban works under the hood—using iptables to dynamically block IPs after repeated failed attempts—and then walk through the more fundamental shift to key-only authentication. Lucas breaks down the exact configuration changes in /etc/ssh/sshd_config, including disabling password authentication and root login. He also shares a concrete example: a small web server that went from thousands of daily bot login attempts to fewer than a dozen after implementing these changes. Luna asks about the risks of losing SSH keys and suggests a backup strategy using a hardware token like a YubiKey. The episode closes with Lucas reflecting on the principle of defense in depth: Fail2ban is a good band-aid, but key-only auth is the real fix. A brief, natural mention of listener support (buy me a coffee dot com slash fexingo) is woven into the conversation near the end.

#Linux #Sysadmin #SSHSecurity #Fail2ban #KeyOnlyAuth #ServerHardening #CyberSecurity #Infosec #DevOps #Iptables #PublicKeyCryptography #YubiKey #BruteForceProtection #DefenseInDepth #ServerAdmin #FexingoBusiness #BusinessPodcast #Technology

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In this episode of Linux Server Admin with Fexingo, Lucas and Luna walk through the practical steps for encrypting a Linux server's disks using LUKS (Linux Unified Key Setup). They explain when encryption matters—for portable drives, cloud instances, and compliance—and when it may not. Lucas demonstrates the exact cryptsetup commands for creating a LUKS container, adding a key slot, opening and mounting it, and configuring auto-unlock via a keyfile on a USB stick. They also cover the performance trade-off (typically a 1-3% CPU hit on modern hardware) and how to test it with dd. Luna asks about recovery if a keyfile is lost, and Lucas explains the backup passphrase strategy. A concrete, no-fluff guide to a critical security practice.

#Linux #ServerEncryption #LUKS #DiskEncryption #cryptsetup #dm-crypt #Security #Sysadmin #Bash #ServerEngineering #Keyfile #DataProtection #Compliance #Technology #LinuxServerAdmin #FexingoBusiness #BusinessPodcast #ITSecurity

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Episode 47 of Linux Server Admin with Fexingo dives into cgroups v2, the modern control group implementation that replaces the fragmented v1 system. Lucas and Luna walk through real server scenarios: limiting CPU shares for noisy neighbors on a shared web host, pinning memory for a critical database container, and configuring IO throttling for backup jobs. They explain how systemd integrates cgroups v2 by default on recent distros like Ubuntu 24.04 and RHEL 9, and show practical commands using systemctl and the cgroup filesystem. The episode includes a concrete example of isolating an Nginx worker from a runaway Python script, with step-by-step limits on cpu.max, memory.max, and io.max. Listeners learn why cgroups v2's single-hierarchy model simplifies delegation and avoids the edge cases that plagued v1. Perfect for sysadmins managing multi-tenant servers or container hosts.

#Linux #Sysadmin #CgroupsV2 #ResourceControl #ServerEngineering #Systemd #ContainerSecurity #PerformanceTuning #Ubuntu2404 #RHEL9 #CPUThrottling #MemoryLimits #IOLimits #Unix #OpenSource #DevOps #FexingoBusiness #BusinessPodcast

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In this episode of Linux Server Admin, Lucas and Luna tackle the often overlooked tuning of NFS (Network File System) on Linux servers. Using a real-world case of a media rendering farm struggling with NFS latency, they walk through the key sysctl settings, mount options, and server-side daemon parameters that can dramatically improve throughput. You'll learn about the `rsize` and `wsize` mount options, the `nfsd` thread count, and how to use `nfsstat` and `iostat` to diagnose bottlenecks. No abstract theory — just practical tuning steps that can save your server from NFS-induced slowdowns. Plus, a quick note on how listener support via buy me a coffee dot com slash fexingo keeps this ad-free show running.

#Linux #NFS #ServerAdmin #Sysadmin #PerformanceTuning #NetworkFileSystem #Storage #FileServer #LinuxTuning #NFSTuning #MediaRendering #Throughput #Latency #Sysctl #MountOptions #Technology #FexingoBusiness #BusinessPodcast

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Episode 45 of Linux Server Admin with Fexingo dives into Stratis, a Linux storage management tool that combines ZFS-like features with native kernel integration. Lucas and Luna explain how Stratis uses a pool-based model, thin provisioning, snapshots, and tiering without the complexity of traditional volume managers. They walk through installing Stratis on RHEL 9, creating a pool from two NVMe drives, provisioning a filesystem, taking a snapshot, and rolling back a simulated data corruption. The hosts also discuss where Stratis fits alongside LVM and ZFS, and scenarios where it excels—like container host storage or virtual machine disk backends. No abstract theory; every command is runnable. The episode includes a brief, natural mention of listener support at buy me a coffee dot com slash fexingo.

#Linux #Stratis #StorageManagement #RHEL #SystemAdministration #FileSystem #Snapshots #ThinProvisioning #NVMe #Technology #ServerAdmin #Podcast #FexingoBusiness #BusinessPodcast #Sysadmin #Bash #OpenSource #RedHat

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In this episode of Linux Server Admin with Fexingo, Lucas and Luna dive into the practical art of iptables on Linux. They start with a real-world scenario: a misconfigured firewall that locked out a developer's SSH session. From there, they explore three specific iptables use cases that go beyond basic port blocking—rate-limiting inbound connections to prevent brute-force attacks, using connection tracking to allow established traffic while blocking new malicious packets, and setting up a simple but effective DMZ with NAT rules for a web server. Lucas explains the difference between iptables chains (INPUT, OUTPUT, FORWARD) and how to inspect counters with 'iptables -L -v'. Luna challenges him on performance overhead and when to switch to nftables. They also cover how to save and restore rules persistently using iptables-save and iptables-restore. By the end, listeners will have a concrete, copyable iptables rule set they can adapt for their own servers. No fluff—just the commands, the logic, and the gotchas.

#iptables #LinuxFirewall #NetworkSecurity #Sysadmin #ServerEngineering #Bash #Linux #Technology #FexingoBusiness #BusinessPodcast #ITSecurity #DevOps #NFtables #CyberSecurity #FirewallRules #ServerHardening #LinuxAdmin #NetworkAdmin

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In this episode, Lucas and Luna dive into logrotate, the unsung hero of Linux server administration. They explore how a single misconfigured logrotate rule can silently fill a disk partition, causing outages. Using a concrete example of a web server that crashed because Apache logs grew unchecked, they explain logrotate's core directives: daily rotation, compression, delay compress, maxage, and postrotate scripts. They also cover practical pitfalls like missing sharedscripts syntax and permissions issues with log files owned by root versus service users. By the end, listeners will know exactly how to audit their existing logrotate configs and prevent disk-full disasters without manual log cleaning.

#Linux #Sysadmin #ServerAdministration #Logrotate #LogManagement #Apachelogs #NginxlLogs #DiskSpace #DevOps #Bash #ServerMaintenance #LinuxTips #Technology #FexingoBusiness #BusinessPodcast #ServerEngineering #Infrastructure #OpenSource

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Episode 42 of Linux Server Admin with Fexingo dives into diagnosing and fixing packet loss on Linux servers. Lucas and Luna explore practical tools like ping, mtr, tcpdump, and ethtool to pinpoint whether the issue is in the network interface, cable, switch, or kernel buffers. They walk through a real-world scenario where a jammed network cable on a Ubuntu server caused 2.3% packet loss, and show how to isolate and resolve it step by step. They also cover checking for dropped packets with netstat -s and interface statistics, and discuss when to involve your network team versus fixing it yourself. By the end, you'll know how to systematically troubleshoot packet loss without guessing.

#LinuxServerAdmin #PacketLoss #NetworkTroubleshooting #Sysadmin #Bash #ServerEngineering #Technology #Podcast #FexingoBusiness #BusinessPodcast #Ubuntu #TCPDump #Ethtool #MTR #Netstat #NetworkInterface #KernelBuffers #Diagnostics

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Memory leaks on Linux servers can silently degrade performance until a process is killed or the system crashes. In this episode, Lucas and Luna walk through a real-world scenario: a Node.js web server that slowly consumes memory over days. They explain how to use tools like 'top', 'ps', '/proc/meminfo', 'smem', and 'valgrind' to identify the offending process, measure memory growth, and trace the leak to its source. They also cover practical prevention strategies, including memory limits with systemd and cgroups, and monitoring with a simple cron script. No theory without practice — listeners get a concrete shell one-liner to log resident set size over time and a checklist for integrating leak detection into CI. Perfect for sysadmins who manage production servers and want to catch leaks before users notice.

#Linux #ServerMemoryLeak #Sysadmin #MemoryDiagnosis #NodeJsMemoryLeak #TopCommand #Valgrind #SystemdMemoryLimit #Cgroups #ResidentSetSize #Smem #ProductionDebugging #PerformanceMonitoring #BashScripting #Fexingo #FexingoTech #TechnologyPodcast #LinuxServerAdmin

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In this episode of Linux Server Admin, Lucas and Luna dive into systemd timers as a modern replacement for cron. They walk through the anatomy of a timer unit file, compare it to traditional cron syntax, and show you how to create your first timer for a daily log rotation script. Lucas explains why systemd timers offer better logging, dependency handling, and debugging capabilities. They also discuss common pitfalls like timezone handling and calendar event syntax. By the end, you'll know how to replace cron jobs with systemd timers for more reliable and maintainable scheduling on your Linux servers.

#Linux #SystemdTimers #CronReplacement #ServerAdministration #Automation #Bash #Sysadmin #Technology #LinuxServer #Systemd #TimerUnits #Scheduling #LogRotation #DevOps #FexingoBusiness #FexingoPodcast #LinuxAdmin #ServerManagement

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