DNS

How to Sync Time with Chrony on RHEL 9 — step-by-step RHEL 9 tutorial on Progressive Robot

How to Sync Time with Chrony on RHEL 9

Accurate time synchronization is not optional on a server — it is a hard requirement. TLS certificate validation fails when the clock is wrong by more than a few minutes. Kerberos authentication rejects tickets with a clock skew over 5 minutes. Cron jobs fire at the wrong time. Log correlation across multiple servers becomes impossible […]

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How to Install and Configure Squid Proxy on FreeBSD 14 — step-by-step FreeBSD 14 tutorial on Progressive Robot

How to Install and Configure Squid Proxy on FreeBSD 14

Introduction This guide explains how to Install and Configure Squid Proxy on FreeBSD 14 on FreeBSD 14. FreeBSD uses the pkg(8) binary package manager, rc.conf(5) for service startup configuration, and pf(4) as its primary packet filter. There is no SELinux or AppArmor — instead, FreeBSD provides the MAC (Mandatory Access Control) framework and Capsicum for […]

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How to Configure Suricata IDS on FreeBSD 14 — step-by-step FreeBSD 14 tutorial on Progressive Robot

How to Configure Suricata IDS on FreeBSD 14

Introduction Deploying configure suricata ids on freebsd 14 on a FreeBSD 14 machine differs from Linux in several important ways: packages come from the FreeBSD Ports Collection or the binary pkg repository, services are registered in /etc/rc.conf via sysrc(8), and firewall rules are written in pf.conf(5) syntax. This tutorial stays entirely within the standard base […]

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Common Problems 114554

SSH Key Login Rejected on RHEL 9

🟡 Medium   ⏱ 5–30 min  Last verified: 24 December 2023 📖 ~1 min read Table of contents Symptom & Impact Environment & Reproduction Root Cause Analysis Quick Triage Step-by-Step Diagnosis Solution – Primary Fix Solution – Alternative Approaches Verification & Acceptance Criteria Rollback Plan Prevention & Hardening Related Errors & Cross-Refs References & Further […]

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How to Configure pgBouncer on CentOS Stream 9 — step-by-step CentOS Stream 9 tutorial on Progressive Robot

How to Configure pgBouncer on CentOS Stream 9

Introduction How to Configure pgBouncer on CentOS Stream 9 on CentOS Stream 9 provides administrators with a robust, enterprise-ready workflow that integrates cleanly with systemd, SELinux, firewalld, and the modern AppStream module system. In this tutorial we will walk through every step required, from package installation to verification, so that the resulting configuration is reproducible […]

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How to Automate FreeBSD 14 Server Provisioning with Ansible — step-by-step FreeBSD 14 tutorial on Progressive Robot

How to Automate FreeBSD 14 Server Provisioning with Ansible

Introduction FreeBSD 14 is a UNIX-derived operating system renowned for its network stack performance, ZFS integration, and Jail isolation primitives. Setting up automate freebsd 14 server provisioning with ansible on FreeBSD 14 follows the rc.conf/service(8) paradigm rather than systemd, which means enabling a service and configuring its startup options are done differently from any Linux […]

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Alpine Linux 3.19 — gdnsd — vulnerability — patch and remediation guide — diagnosis and fix on Alpine Linux 3.19

Alpine Linux 3.19 — gdnsd — vulnerability — patch and remediation guide

🟡 Medium   ⏱ 10–30 min  Last verified: 25 May 2026 Affected versions: Alpine Linux 3.19 / fixed in 2.4.3-r0 📖 ~4 min read  •  Source: Alpine secdb entry — gdnsd 2.4.3-r0 Related CVEs: CVE-2019-13952 Upstream summary: Alpine community repository for vv3.19 ships gdnsd 2.4.3-r0 which addresses CVE-2019-13952. Table of contents Symptom & Impact Environment […]

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Common Problems 120001

Debian 12 – Network Interface Rename Breaks Connectivity – Persistent Naming Fix

🟠 High   ⏱ 5–30 min  Last verified: 23 December 2023 Affected versions: Debian 12 📖 ~1 min read Table of contents Symptom & Impact Environment & Reproduction Root Cause Analysis Quick Triage Step-by-Step Diagnosis Solution – Primary Fix Solution – Alternative Approaches Verification & Acceptance Criteria Rollback Plan Prevention & Hardening Related Errors & […]

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How to Install Python 3.12 on Debian 12 — step-by-step Debian 12 tutorial on Progressive Robot

How to Install Python 3.12 on Debian 12

Introduction Deploying install python 3.12 on debian 12 on a Debian 12 Bookworm machine is straightforward thanks to Debian’s policy-compliant packaging. Unlike rpm-based distributions, Debian stores configuration helpers in /etc/default/, uses update-rc.d for older init scripts, and provides dpkg-reconfigure for interactive package configuration. This tutorial stays on the systemd path throughout. Prerequisites You will need […]

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How to Install and Configure Valkey on Debian 12 — step-by-step Debian 12 tutorial on Progressive Robot

How to Install and Configure Valkey on Debian 12

Introduction This guide explains how to Install and Configure Valkey on Debian 12 on Debian 12 Bookworm. Debian Bookworm uses systemd for service management, nftables as the underlying packet filter (with ufw or iptables front-ends still available), and AppArmor for mandatory access control. Every command is designed for a minimal Debian 12 install with the […]

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