DNS

Common Problems 117041

Ubuntu 22.04 LTS – NTP not synchronized causes Kerberos and TLS failures – Fix & Prevention

🟠 High   ⏱ 5–30 min  Last verified: 20 May 2026 Affected versions: Ubuntu 22.04 LTS 📖 ~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 117541

Ubuntu 20.04 LTS – UFW policy change blocks SSH and remote administration – Fix & Prevention

🔴 Critical   ⏱ 5–30 min  Last verified: 20 May 2026 Affected versions: Ubuntu 20.04 LTS 📖 ~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 115032

RHEL 8 AppStream Module Defaults Break Package Installation

🟡 Medium   ⏱ 5–30 min  Last verified: 20 May 2026 Affected versions: 8.6 8.7 8.8 8.9 8.10 📖 ~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 […]

Read more
Common Problems 115538

RHEL 7 firewalld Rich Rule Order Breaks DNAT

🟡 Medium   ⏱ 5–30 min  Last verified: 20 May 2026 📖 ~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 118046

Ubuntu 18.04 LTS – UFW policy change blocks SSH and remote administration – Fix & Prevention

🔴 Critical   ⏱ 5–30 min  Last verified: 20 May 2026 Affected versions: Ubuntu 18.04 LTS 📖 ~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 116047

Ubuntu 26.04 LTS – OpenSSH login denied due to strict AllowUsers policy – Fix & Prevention

🟠 High   ⏱ 5–30 min  Last verified: 20 May 2026 Affected versions: Ubuntu 26.04 LTS 📖 ~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
NetBSD 10.0 — dnsdist — multiple vulnerabilities (7 CVEs) — patch and remediation guide — diagnosis and fix on NetBSD 10.0

NetBSD 10.0 — dnsdist — multiple vulnerabilities (7 CVEs) — patch and remediation guide

🟠 High   ⏱ 15–60 min  Last verified: 25 May 2026 Affected versions: NetBSD 10.0 📖 ~4 min read  •  Source: pkgsrc audit-packages entry Related CVEs: CVE-2025-30194 CVE-2017-7557 CVE-2018-14663 CVE-2016-7069 CVE-2025-30187 CVE-2024-25581 CVE-2025-30193 Upstream summary: pkgsrc audit-packages flagged dnsdist<1.9.9 for vulnerability class 'use-after-free'. Reference: https://nvd.nist.gov/vuln/detail/CVE-2025-30194 Table of contents Symptom & Impact Environment & Reproduction Root […]

Read more
NetBSD 10.0 — dnsmasq — multiple vulnerabilities (20 CVEs) — patch and remediation guide — diagnosis and fix on NetBSD 10.0

NetBSD 10.0 — dnsmasq — multiple vulnerabilities (20 CVEs) — patch and remediation guide

🟠 High   ⏱ 15–60 min  Last verified: 25 May 2026 Affected versions: NetBSD 10.0 📖 ~4 min read  •  Source: pkgsrc audit-packages entry Related CVEs: CVE-2009-2957 CVE-2022-0934 CVE-2008-1447 CVE-2017-14492 CVE-2017-14493 CVE-2017-15107 CVE-2019-14513 CVE-2020-25681  +12 more Upstream summary: pkgsrc audit-packages flagged dnsmasq<2.50 for vulnerability class 'arbitrary-code-execution'. Reference: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2009-2957 Table of contents Symptom & Impact Environment […]

Read more
Common Problems 117031

Ubuntu 22.04 LTS – ext4 filesystem errors force read-only remount – Fix & Prevention

🟠 High   ⏱ 5–30 min  Last verified: 19 May 2026 Affected versions: Ubuntu 22.04 LTS 📖 ~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 117531

Ubuntu 20.04 LTS – SSH key authentication fails due to permission errors – Fix & Prevention

🟠 High   ⏱ 5–30 min  Last verified: 19 May 2026 Affected versions: Ubuntu 20.04 LTS 📖 ~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
CHAT