Troubleshooting

Common Problems 114988

RHEL 8 XFS Filesystem Remounts Read-Only After I/O Errors

🟡 Medium   ⏱ 5–30 min  Last verified: 11 August 2020 📖 ~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 […]

Read more
How to Secure PostgreSQL on SLES 12 — step-by-step SUSE Linux Enterprise 12 tutorial on Progressive Robot

How to Secure PostgreSQL on SLES 12

Introduction This tutorial covers How to Secure PostgreSQL on SLES 12 on SLES 12. SLES 12 (SUSE Linux Enterprise Server 16) is SUSE’s enterprise-grade Linux distribution. It uses the zypper package manager, AppArmor for mandatory access control, and systemctl for service management. Prerequisites Ensure your SLES 12 system is up to date: zypper refresh && […]

Read more
Common Problems 114949

RHEL 8 – NetworkManager Profile Bound to Wrong Interface

🟡 Medium   ⏱ 5–30 min  Last verified: 11 August 2020 📖 ~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 […]

Read more
Common Problems 114933

RHEL 8 SELinux AVC denies web application write access

🟡 Medium   ⏱ 5–30 min  Last verified: 11 August 2020 📖 ~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 […]

Read more
Ubuntu 18.04 — grub2 — multiple vulnerabilities (10 CVEs) — patch and remediation guide — diagnosis and fix on Ubuntu 18.04

Ubuntu 18.04 — grub2 — multiple vulnerabilities (10 CVEs) — patch and remediation guide

🟠 High   ⏱ 15–60 min  Last verified: 11 August 2020 Affected versions: Ubuntu 18.04 (bionic) 📖 ~4 min read  •  Source: Ubuntu Security Notice USN-4432-2 Related CVEs: https://launchpad.net/bugs/1889556 https://wiki.ubuntu.com/SecurityTeam/KnowledgeBase/GRUB2SecureBootBypass CVE-2020-10713 CVE-2020-14308 CVE-2020-14309 CVE-2020-14310 CVE-2020-14311 CVE-2020-15705  +2 more Upstream summary: USN-4432-1 fixed vulnerabilities in GRUB2 affecting Secure Boot environments. Unfortunately, the update introduced regressions for […]

Read more
How to Configure SSL/TLS Client Certificate Authentication on Debian 10 — step-by-step Debian 10 tutorial on Progressive Robot

How to Configure SSL/TLS Client Certificate Authentication on Debian 10

Introduction How to Configure SSL/TLS Client Certificate Authentication on Debian 10 is a fundamental operation for any administrator maintaining a Debian 10 Buster server. Debian 10 Buster ships with the Linux 6.12 kernel, updated toolchains, and a fully refreshed package archive — meaning version numbers, configuration file paths, and some dependency chains differ from Debian […]

Read more
How to Configure a Read-Only Domain Controller (RODC) on Windows Server 2016 — step-by-step Windows Server 2016 tutorial on Progressive Robot

How to Configure a Read-Only Domain Controller (RODC) on Windows Server 2016

How to Set Up Windows Server 2016 Read-Only Domain Controller A Read-Only Domain Controller (RODC) is a special type of Domain Controller introduced in Windows Server 2008 that holds a read-only copy of the Active Directory database. RODCs are designed for deployment in locations where physical security cannot be guaranteed, such as branch offices, edge […]

Read more
Common Problems 121558

DNS Resolution Intermittently Fails on Server

🟠 High   ⏱ 5–30 min  Last verified: 10 August 2020 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 & […]

Read more
Common Problems 121017

Debian 10 Temporary Failure Resolving During apt update

🟡 Medium   ⏱ 5–30 min  Last verified: 10 August 2020 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 & […]

Read more
Ubuntu 16.04 — grub2-signed — multiple vulnerabilities (10 CVEs) — patch and remediation guide — diagnosis and fix on Ubuntu 16.04

Ubuntu 16.04 — grub2-signed — multiple vulnerabilities (10 CVEs) — patch and remediation guide

🟠 High   ⏱ 15–60 min  Last verified: 10 August 2020 Affected versions: Ubuntu 16.04 (xenial) 📖 ~4 min read  •  Source: Ubuntu Security Notice USN-4432-2 Related CVEs: https://launchpad.net/bugs/1889556 https://wiki.ubuntu.com/SecurityTeam/KnowledgeBase/GRUB2SecureBootBypass CVE-2020-10713 CVE-2020-14308 CVE-2020-14309 CVE-2020-14310 CVE-2020-14311 CVE-2020-15705  +2 more Upstream summary: USN-4432-1 fixed vulnerabilities in GRUB2 affecting Secure Boot environments. Unfortunately, the update introduced regressions for […]

Read more
CHAT