AdguardTeam/AdGuardHome · warning

failed to get addresses for interface %s: %w

Error message

failed to get addresses for interface %s: %w

What it means

Thrown by newNetInterfaceJSON when the Go standard library's net.Interface.Addrs() fails while enumerating a network interface for GET /control/dhcp/interfaces. The wrapped syscall error usually reports a deleted interface (ENODEV), permission problems, or a /proc/net state that changed during enumeration.

Source

Thrown at internal/dhcpd/http_unix.go:470

		if jsonIface != nil {
			resp[iface.Name] = jsonIface
		}
	}

	aghhttp.WriteJSONResponseOK(ctx, l, w, r, resp)
}

// newNetInterfaceJSON creates a JSON object from a [net.Interface] iface.
// l and cmdCons must not be nil.
func newNetInterfaceJSON(
	ctx context.Context,
	l *slog.Logger,
	iface net.Interface,
	cmdCons executil.CommandConstructor,
) (out *netInterfaceJSON, err error) {
	addrs, err := iface.Addrs()
	if err != nil {
		return nil, fmt.Errorf(
			"failed to get addresses for interface %s: %w",
			iface.Name,
			err,
		)
	}

	out = &netInterfaceJSON{
		Name:         iface.Name,
		HardwareAddr: iface.HardwareAddr.String(),
	}

	if iface.Flags != 0 {
		out.Flags = iface.Flags.String()
	}

	// We don't want link-local addresses in JSON, so skip them.
	for _, addr := range addrs {
		ipNet, ok := addr.(*net.IPNet)

View on GitHub (pinned to b41aefbe51)

Solutions

1. Retry the request — transient interface churn usually resolves within milliseconds
2. If it persists, check the named interface still exists with ip link show <name>
3. In containers, ensure /proc is mounted and the runtime grants network visibility (e.g. don't use a network-degraded sandbox)
4. Avoid triggering the interfaces endpoint in tight loops while scripts are flapping interfaces

if _, err := net.InterfaceByName(iface.Name); err != nil {
    return // interface vanished; skip it instead of calling Addrs
}

var out *netInterfaceJSON
var err error
for i := 0; i < 3; i++ {
    out, err = newNetInterfaceJSON(log, iface, cmdCons)
    if err == nil { break }
    time.Sleep(50 * time.Millisecond)
}

When it happens

Trigger: Calling GET /control/dhcp/interfaces while an interface (VPN tun, docker veth, USB NIC) is being created or destroyed, so Addrs() races with the interface disappearing; or running in a restricted container where reading interface addresses is denied.

Common situations: Dashboard loading the DHCP page exactly when a VPN connects/disconnects; Docker/Kubernetes environments with ephemeral veth devices; chroots without /proc mounted; heavily transient network namespaces.

Related errors

• checking static ip: %w
• setting static ip: %w
• starting dhcp server: %w
• invalid bind_host value: %s
• %v is not an IPv4 %s

AI-assisted analysis of AdguardTeam/AdGuardHome@b41aefbe51 (2026-08-27). Data as JSON: /api/errors/381f3aa7c5770c15. Report an issue: GitHub.