slackhq/nebula · error

failed to get ip interface: %w

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.

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)

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when luid.IPInterface(windows.AF_INET) fails — typically because the adapter was removed, is disabled, or the LUID is no longer valid at route-config time.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: %w
• create TUN device failed: %w
• failed to set address: %w
• FwpmFilterAdd0: 0x%x
• ErrInvalidLocalIP

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