Firewall

Common Problems 124175

Oracle Linux 10 – sudo rules ignored because sssd cache is stale – Fix & Prevention

🟠 High   ⏱ 5–30 min  Last verified: 20 May 2026 Affected versions: Oracle Linux 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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Common Problems 114112

RHEL 10 – kdump service fails to reserve crashkernel memory – Fix & Prevention

🔴 Critical   ⏱ 5–30 min  Last verified: 20 May 2026 Affected versions: RHEL 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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Common Problems 115609

RHEL 7 yum repository unreachable through enterprise proxy

🟡 Medium   ⏱ 5–30 min  Last verified: 20 May 2026 Affected versions: RHEL 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 & Hardening Related Errors & […]

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Common Problems 118599

Ubuntu 16.04 LTS Chrony Not Syncing Due to Firewall Policy

🟡 Medium   ⏱ 5–30 min  Last verified: 20 May 2026 Affected versions: 16.04 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 & […]

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Common Problems 124166

Oracle Linux 10 – kdump service fails to reserve crashkernel memory – Fix & Prevention

🔴 Critical   ⏱ 5–30 min  Last verified: 20 May 2026 Affected versions: Oracle Linux 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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Common Problems 115113

RHEL 8 Postfix cannot send mail due to firewall and SELinux policy

🟡 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 […]

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Common Problems 124157

Oracle Linux 10 – rsyslog not forwarding logs over TLS to SIEM – Fix & Prevention

🟠 High   ⏱ 5–30 min  Last verified: 20 May 2026 Affected versions: Oracle Linux 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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Common Problems 119130

Ubuntu 14.04 LTS SNMP Monitoring Gaps After Community String Rotation

🟡 Medium   ⏱ 5–30 min  Last verified: 20 May 2026 Affected versions: 14.04 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 & […]

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Common Problems 114103

RHEL 10 – rsyslog not forwarding logs over TLS to SIEM – Fix & Prevention

🟠 High   ⏱ 5–30 min  Last verified: 20 May 2026 Affected versions: RHEL 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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Common Problems 114572

Firewalld Rich Rule Order Producing Unexpected Drops

🟡 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 […]

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