Operations

Ubuntu 20.04 — linux-oracle-5.8 — multiple vulnerabilities (20 CVEs) — patch and remediation guide — diagnosis and fix on Ubuntu 20.04

Ubuntu 20.04 — linux-oracle-5.8 — multiple vulnerabilities (20 CVEs) — patch and remediation guide

🟠 High   ⏱ 15–60 min  Last verified: 7 December 2021 Affected versions: Ubuntu 20.04 (focal) 📖 ~4 min read  •  Source: Ubuntu Security Notice USN-5050-1 Related CVEs: CVE-2020-26558 CVE-2021-0129 CVE-2021-28691 CVE-2021-3564 CVE-2021-3573 CVE-2021-38208 CVE-2021-23134 CVE-2021-32399  +12 more Upstream summary: It was discovered that the bluetooth subsystem in the Linux kernel did not properly perform […]

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Ubuntu 20.04 — atftp — multiple vulnerabilities (3 CVEs) — patch and remediation guide — diagnosis and fix on Ubuntu 20.04

Ubuntu 20.04 — atftp — multiple vulnerabilities (3 CVEs) — patch and remediation guide

🟡 Medium   ⏱ 10–30 min  Last verified: 7 December 2021 Affected versions: Ubuntu 20.04 (focal) 📖 ~4 min read  •  Source: Ubuntu Security Notice USN-6334-1 Related CVEs: CVE-2020-6097 CVE-2021-41054 CVE-2021-46671 Upstream summary: Peter Wang discovered that atftp did not properly manage certain inputs. A remote attacker could send a specially crafted tftp request to […]

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AlmaLinux 8 — libvncserver — multiple vulnerabilities (6 CVEs) — patch and remediation guide — diagnosis and fix on AlmaLinux 8

AlmaLinux 8 — libvncserver — multiple vulnerabilities (6 CVEs) — patch and remediation guide

🟠 High   ⏱ 15–60 min  Last verified: 25 May 2026 Affected versions: AlmaLinux 8 📖 ~4 min read  •  Source: AlmaLinux ALSA ALSA-2020:3385 Related CVEs: CVE-2017-18922 CVE-2018-21247 CVE-2019-20839 CVE-2020-14397 CVE-2020-14405 CVE-2020-25708 Upstream summary: LibVNCServer is a C library that enables you to implement VNC server functionality into own programs. Security Fix(es): * libvncserver: websocket […]

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How to Install and Configure OpenVPN on RHEL 7 — step-by-step RHEL 7 tutorial on Progressive Robot

How to Install and Configure OpenVPN on RHEL 7

How to Install and Configure OpenVPN on RHEL 7 OpenVPN is one of the most widely deployed VPN solutions in the enterprise, valued for its flexibility, strong encryption, and compatibility across nearly every operating system. On RHEL 7, OpenVPN is not included in the base repositories but is available from EPEL. Building a proper PKI […]

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Oracle Linux 8 — ruby:2.7 security, bug fix, and — enhancement update — new behaviour and fixes — diagnosis and fix on Oracle Linux 8

Oracle Linux 8 — ruby:2.7 security, bug fix, and — enhancement update — new behaviour and fixes (ELSA-2021-2584)

🟡 Medium   ⏱ 10–30 min  Last verified: 6 December 2021 Affected versions: Oracle Linux 8 📖 ~4 min read  •  Source: ELSA advisory ELSA-2021-2584 Related CVEs: CVE-2020-25613 CVE-2021-28965 Table of contents Symptom & Impact Environment & Reproduction Root Cause Analysis Quick Triage Step-by-Step Diagnosis Solution – Primary Fix Solution – Alternative Approaches Verification & […]

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Common Problems 121531

Debian 9 – nftables Rules Missing After Reboot – Persistent Firewall Setup

🟠 High   ⏱ 5–30 min  Last verified: 6 December 2021 Affected versions: Debian 9 📖 ~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 Set Up Fluentd on CentOS Stream 9 — step-by-step CentOS Stream 9 tutorial on Progressive Robot

How to Set Up Fluentd on CentOS Stream 9

Introduction How to Set Up Fluentd 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 […]

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Common Problems 121180

Firewall Rules Block Application Traffic

🟠 High   ⏱ 5–30 min  Last verified: 6 December 2021 Affected versions: Debian 10 📖 ~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 Configure Chef Client on IBM AIX 7.1 — step-by-step IBM AIX 7.1 tutorial on Progressive Robot

How to Configure Chef Client on IBM AIX 7.1

Introduction IBM AIX 7.1 is the latest release of IBM’s enterprise-grade UNIX operating system, running on IBM Power Systems hardware. Known for its reliability, security, and performance in mission-critical environments, AIX 7.1 introduces enhanced virtualization, security hardening, and cloud integration features. This guide covers how to configure chef client on ibm aix 7.1 on IBM […]

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