🟠 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

Server boots without expected network, breaking remote access and services.

Environment & Reproduction

Common after virtual hardware changes or driver updates.

ifconfig -l
cat /etc/rc.conf | grep ifconfig

Root Cause Analysis

rc.conf binds IP settings to an interface name that changed.

Quick Triage

Identify current interface names and test temporary DHCP/static assignment.

ifconfig
dhclient

Step-by-Step Diagnosis

Compare saved rc.conf entries with current device inventory and logs.

dmesg | egrep 'em|igb|ix|vtnet'
grep -n 'ifconfig_' /etc/rc.conf
Illustrative mockup for freebsd-14 — nic_rename_problem
Configured interface no longer present — Illustrative mockup — Progressive Robot

Solution – Primary Fix

Update interface keys in rc.conf and restart netif/routing services.

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sysrc ifconfig_vtnet0='inet 10.0.0.20/24'
service netif restart
service routing restart
Illustrative mockup for freebsd-14 — nic_rename_fixed
Interface mapping restored — Illustrative mockup — Progressive Robot

Solution – Alternative Approaches

Use bridge/VLAN abstraction so service IPs are less tied to raw NIC names.

Verification & Acceptance Criteria

Expected IP and default route are present and reachable.

ifconfig vtnet0
netstat -rn

Rollback Plan

Restore previous rc.conf from backup and apply temporary rescue network config.

Prevention & Hardening

Track interface naming in change plans and validate post-reboot connectivity checks.

no carrier, interface does not exist, network unreachable after reboot.

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

FreeBSD rc.conf networking and interface configuration handbook sections.

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