slackhq/nebula · error

failed to get ip interface

Error message

failed to get ip interface: %w

What it means

addRoutes failed to retrieve the IPv4 IP interface for the TUN adapter via luid.IPInterface(windows.AF_INET). The library wraps the winipcfg error before applying MTU/metric settings. Getting this means the interface disappeared or is not fully initialized in Windows.

Solutions

1. Restart the nebula service to recreate the TUN device
2. Check the adapter exists and is enabled in Device Manager / Get-NetAdapter
3. Disable conflicting VPN/filter software that tears down wintun adapters
4. Verify the wrapped error code (ERROR_NOT_FOUND usually = adapter gone)
5. Update wintun driver if failures recur after sleep/resume

// confirm the adapter is present before route setup
adapters, _ := winipcfg.GetAdaptersAddresses(windows.AF_INET, 0)
found := false
for _, a := range adapters {
    if a.LUID == luid { found = true }
}
if !found { return errors.New("TUN adapter vanished before route setup") }

if err := tun.Activate(); err != nil {
    if strings.Contains(err.Error(), "failed to get ip interface") {
        time.Sleep(500 * time.Millisecond)
        return tun.Activate() // retry after adapter settles
    }
    return err
}

When it happens

Trigger: Called from Activate() or reload() when luid.IPInterface(windows.AF_INET) fails — typically because the adapter was removed, is disabled, or the LUID is no longer valid at route-config time.

Common situations: VPN adapter deleted by antivirus/VPN conflict software between creation and route setup; adapter disabled; rapid reload racing with teardown; driver in a bad state after sleep/resume.

Related errors

• failed to set ip interface
• create TUN device failed
• failed to set address
• FwpmFilterAdd0: 0x
• add v4 filter

AI-assisted analysis of slackhq/nebula@dd8f660c0a (2026-09-03). Data as JSON: /api/errors/0efbd70119e1fc84. Report an issue: GitHub.

Appendix: source

Thrown at overlay/tun_windows.go:215

				retErr.Log(t.l)
				continue
			} else {
				return retErr
			}
		} else {
			t.l.Info("Added route", "route", r)
		}

		if !foundDefault4 {
			if r.Cidr.Bits() == 0 && r.Cidr.Addr().BitLen() == 32 {
				foundDefault4 = true
			}
		}
	}

	ipif, err := luid.IPInterface(windows.AF_INET)
	if err != nil {
		return fmt.Errorf("failed to get ip interface: %w", err)
	}

	ipif.NLMTU = uint32(t.MTU)
	if foundDefault4 {
		ipif.UseAutomaticMetric = false
		ipif.Metric = 0
	}

	if err := ipif.Set(); err != nil {
		return fmt.Errorf("failed to set ip interface: %w", err)
	}
	return nil
}

func (t *winTun) removeRoutes(routes []Route) error {
	luid := winipcfg.LUID(t.tun.LUID())

	for _, r := range routes {

View on GitHub (pinned to dd8f660c0a)