🟠 High   ⏱ 5–30 min  Last verified: 19 May 2026
Affected versions: RHEL 10.0 RHEL 10.1

📖 ~1 min read

Table of contents
  1. Symptom & Impact
  2. Environment & Reproduction
  3. Root Cause Analysis
  4. Quick Triage
  5. Step-by-Step Diagnosis
  6. Solution – Primary Fix
  7. Solution – Alternative Approaches
  8. Verification & Acceptance Criteria
  9. Rollback Plan
  10. Prevention & Hardening
  11. Related Errors & Cross-Refs
  12. References & Further Reading

Symptom & Impact

Application ports appear open in policy docs but client traffic is still denied.

Environment & Reproduction

Occurs when layered firewalld rich rules conflict with service-level allowances.

sudo firewall-cmd --list-all --zone=public

Root Cause Analysis

A higher-priority rich rule drops packets before generic service allow rules are evaluated.

Quick Triage

Review runtime and permanent zone configs and packet counters.

sudo firewall-cmd --list-rich-rules --zone=public

Step-by-Step Diagnosis

Trace active zone bindings and inspect deny rules with source constraints.

sudo firewall-cmd --get-active-zones
Illustrative mockup for rhel-10 — firewalld_rich_rules_list
Listing rich rules by zone — Illustrative mockup — Progressive Robot

Solution – Primary Fix

Remove or narrow conflicting rich rule and reload firewalld policy.

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sudo firewall-cmd --permanent --zone=public --remove-rich-rule='rule family=ipv4 source address=0.0.0.0/0 drop' && sudo firewall-cmd --reload
Illustrative mockup for rhel-10 — firewalld_remove_rule
Removing conflicting rich rule — Illustrative mockup — Progressive Robot

Solution – Alternative Approaches

Create dedicated zone per interface and apply explicit allowlist with logging.

Verification & Acceptance Criteria

Service handshake succeeds from approved sources and denied sources remain blocked.

Rollback Plan

Re-add previous rich rule from backup and investigate with temporary log-only rule.

Prevention & Hardening

Require change review for rich rules and run continuous policy diff checks.

Cross-check nftables direct rules and cloud security group restrictions.

Related tutorial: View the step-by-step tutorial for rhel-10.

View all rhel-10 tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

RHEL firewalld zone design and rich rule documentation.

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