//nbkelley /homelab

Troubleshooting Network Interface Changes#

What Was Established#

When replacing a physical Network Interface Card (NIC)—for example, swapping a 2.5GbE card for a 1GbE card—the system will lose connectivity if the software configuration still references the old interface name.

Key Decisions#

Connectivity loss after a hardware swap is usually due to a mismatch in the bridge-ports setting within the network configuration. The new NIC will likely have a different kernel interface name (e.g., changing from enp0s1 to enp0s2).

Current Configuration#

Steps to resolve connectivity loss after a NIC swap:

  1. Identify the new interface name:

ip a

2. **Update the bridge configuration**:
   Edit `/etc/network/interfaces` and update the `bridge-ports` line under `vmbr0` to match the new interface name found in step 1.
3. **Check for driver/kernel issues**:
   If the interface does not appear, check `dmesg` for errors:
   ```bash
dmesg | grep eth
  1. Apply changes:

systemctl restart networking


## Historical Notes
This troubleshooting logic was applied to a specific case of transitioning from 2.5GbE to 1GbE hardware in March 2025.

## Open Questions
N/A

## Related Pages
[Proxmox Network Configuration](/docs/infrastructure/proxmox_network/), [Proxmox Network Troubleshooting](/docs/infrastructure/proxmox_networking/)

## Sources
Converting MB to GB Calculation Example · `ingested/chats/converting_mb_to_gb_calculation_example.md`