Ubuntu 16.04 LTS iptables rules lost after reboot

📖 ~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

Firewall controls disappear after restart, exposing or blocking traffic unexpectedly.

Environment & Reproduction

Occurs when runtime iptables updates are not saved to persistent config.

Root Cause Analysis

Netfilter rules exist only in memory and are not restored during boot sequence.

Quick Triage

Capture current policy and verify whether persistent tooling is installed and enabled.

Step-by-Step Diagnosis

Inspect boot logs and persistence files for load errors or absent rule snapshots.

Solution – Primary Fix

Install persistence package, save ruleset, and enable auto-restore on boot.

Solution – Alternative Approaches

Manage policy via configuration management or migrate to nftables-capable platforms.

Verification & Acceptance Criteria

Ruleset survives reboot and expected inbound/outbound filters remain effective.

Rollback Plan

Restore prior rules snapshot and disable faulty persistence script if needed.

Prevention & Hardening

Track firewall drift and validate rules after every reboot or deployment.

Related Errors & Cross-Refs

Connection refused after reboot, unexpected open ports, and policy chain missing.

Related tutorial: View the step-by-step tutorial for Ubuntu 16.04 LTS.

View all Ubuntu 16.04 LTS tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

iptables persistence practices for Ubuntu 16.04 security operations.