Operations

How to Configure DHCP Failover on Windows Server 2016 — step-by-step Windows Server 2016 tutorial on Progressive Robot

How to Configure DHCP Failover on Windows Server 2016

How to Configure High Availability for DHCP with DHCP Failover on Windows Server 2016 DHCP (Dynamic Host Configuration Protocol) is a critical network service — when it fails, new devices cannot obtain IP addresses and existing leases eventually expire, causing network outages. Windows Server 2016 includes DHCP Failover, a feature that allows two DHCP servers […]

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Ubuntu 16.04 — pulseaudio — multiple vulnerabilities (4 CVEs) — patch and remediation guide — diagnosis and fix on Ubuntu 16.04

Ubuntu 16.04 — pulseaudio — multiple vulnerabilities (4 CVEs) — patch and remediation guide

🟡 Medium   ⏱ 10–30 min  Last verified: 22 March 2021 Affected versions: Ubuntu 16.04 (xenial) 📖 ~4 min read  •  Source: Ubuntu Security Notice USN-4640-1 Related CVEs: CVE-2020-16123 CVE-2020-15710 CVE-2020-11931 https://launchpad.net/bugs/1877102 Upstream summary: James Henstridge discovered that an Ubuntu-specific patch caused PulseAudio to incorrectly handle snap client connections. An attacker could possibly use this […]

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Ubuntu 14.04 — fail2ban — vulnerability — patch and remediation guide — diagnosis and fix on Ubuntu 14.04

Ubuntu 14.04 — fail2ban — vulnerability — patch and remediation guide

🟢 Low   ⏱ 5–15 min  Last verified: 22 March 2021 Affected versions: Ubuntu 14.04 (trusty) 📖 ~4 min read  •  Source: Ubuntu Security Notice USN-5232-1 Related CVEs: CVE-2021-32749 Upstream summary: Jakub Żoczek discovered that certain Fail2ban actions handled whois responses in an insecure way. If Fail2ban was configured to use certain mail actions like […]

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openSUSE Tumbleweed — libfreeimage3 — multiple vulnerabilities (5 CVEs) — patch and remediation guide — diagnosis and fix on openSUSE Tumbleweed

openSUSE Tumbleweed — libfreeimage3 — multiple vulnerabilities (5 CVEs) — patch and remediation guide

🟠 High   ⏱ 15–60 min  Last verified: 25 May 2026 Affected versions: openSUSE Tumbleweed 📖 ~4 min read  •  Source: SUSE security advisory (see also SUSE bugzilla) Related CVEs: CVE-2020-21428 CVE-2019-12211 CVE-2015-0852 CVE-2016-5684 CVE-2019-12213 Upstream summary: Buffer Overflow vulnerability in function LoadRGB in PluginDDS.cpp in FreeImage 3.18.0 allows remote attackers to run arbitrary code […]

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SLES 12 — glib-networking — vulnerability — patch and remediation guide — diagnosis and fix on SLES 12

SLES 12 — glib-networking — vulnerability — patch and remediation guide

🟡 Medium   ⏱ 10–30 min  Last verified: 22 March 2021 Affected versions: SLES 12 📖 ~4 min read  •  Source: SUSE advisory SUSE-SU-2021:3944-1 (see also SUSE bugzilla) Related CVEs: CVE-2020-13645 Upstream summary: In GNOME glib-networking through 2.64.2, the implementation of GTlsClientConnection skips hostname verification of the server's TLS certificate if the application fails to […]

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How to Configure Nginx as a Reverse Proxy on RHEL 7 — step-by-step RHEL 7 tutorial on Progressive Robot

How to Configure Nginx as a Reverse Proxy on RHEL 7

How to Configure Nginx as a Reverse Proxy on RHEL 7 A reverse proxy sits in front of one or more backend application servers, forwarding incoming client requests and returning the backend responses. Nginx is exceptionally well-suited for this role due to its event-driven architecture and low memory footprint. On RHEL 7, a common pattern […]

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Arch Linux — dotnet-runtime — multiple vulnerabilities (5 CVEs) — patch and remediation guide — diagnosis and fix on Arch Linux

Arch Linux — dotnet-runtime — multiple vulnerabilities (5 CVEs) — patch and remediation guide

🟠 High   ⏱ 15–60 min  Last verified: 25 May 2026 Affected versions: Arch Linux (rolling release) 📖 ~4 min read  •  Source: Arch ASA ASA-202103-20 Related CVEs: CVE-2021-26701 CVE-2021-24112 CVE-2021-1723 CVE-2021-1721 CVE-2021-31204 Upstream summary: Type: arbitrary code execution. Status: Fixed. Affected: 5.0.3.sdk103-2. Fixed in: 5.0.4.sdk104-1. Group: AVG-1698. Table of contents Symptom & Impact Environment […]

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Oracle Linux 8 — redis:6 security, bug fix, and — enhancement update — new behaviour and fixes — diagnosis and fix on Oracle Linux 8

Oracle Linux 8 — redis:6 security, bug fix, and — enhancement update — new behaviour and fixes (ELSA-2022-7541)

🟢 Low   ⏱ 5–15 min  Last verified: 21 March 2021 Affected versions: Oracle Linux 8 📖 ~4 min read  •  Source: ELSA advisory ELSA-2022-7541 Related CVEs: CVE-2022-24736 CVE-2022-24735 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 118526

Ubuntu 16.04 LTS – swap not enabled after reboot

🟡 Medium   ⏱ 5–30 min  Last verified: 21 March 2021 Affected versions: Ubuntu 16.04 LTS Ubuntu 16.04 Ubuntu 16.04.7 📖 ~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 […]

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Common Problems 115086

RHEL 8 auditd Backlog Limit Reached Drops Security Events

🟡 Medium   ⏱ 5–30 min  Last verified: 21 March 2021 📖 ~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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