🟠 High   ⏱ 5–30 min  Last verified: 19 May 2026
Affected versions: FreeBSD 14

📖 ~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

Driver or virtualization changes can rename interfaces, breaking static bindings and firewall macros.

Environment & Reproduction

No network on boot, service bind failures, and pf rules referencing missing interface names.

Root Cause Analysis

Systems with em, igb, vtnet, or vmx adapters where interface inventory changed.

Quick Triage

Console access and network maintenance window to avoid accidental lockout.

Step-by-Step Diagnosis

[image_ref: 0] Run ifconfig -l; ifconfig -a; dmesg | grep -E “(em|igb|vtnet|vmx)”; grep -E “ifconfig_|defaultrouter” /etc/rc.conf.

Illustrative mockup for freebsd-14 — terminal_or_shell
ifconfig output showing current interface names and addresses — Illustrative mockup — Progressive Robot

Solution – Primary Fix

[image_ref: 1] Align /etc/rc.conf interface variables with current ifconfig names and update pf.conf interface macros accordingly.

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Illustrative mockup for freebsd-14 — log_or_config
Comparing rc.conf interface stanzas to actual hardware names — Illustrative mockup — Progressive Robot

Solution – Alternative Approaches

Adjust with sysrc ifconfig_newif=”inet x.x.x.x/yy” and remove obsolete entries using sysrc -x ifconfig_oldif. Restart networking service carefully or reboot during a maintenance window.

Verification & Acceptance Criteria

Interfaces come up on boot, default route is present, and dependent services bind successfully.

Rollback Plan

Reapply previous interface mapping and restore prior routing values from backup files.

Prevention & Hardening

Document interface-to-hardware mapping and validate after hypervisor template updates.

Escalate when driver instability or flapping links persist despite correct naming.

Related tutorial: View the step-by-step tutorial for freebsd-14.

View all freebsd-14 tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

ifconfig(8), rc.conf(5), pf.conf(5), FreeBSD network interface handbook sections.

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