XTLS/Xray-core · warning

failed to delete interface address {address}

Error message

failed to delete interface address {address}

What it means

During teardown (unsetInterfaceAddresses), Xray removes each address it previously added to the TUN link. If netlink.AddrDel fails for any address, this error is collected into a combined error. This is cleanup-path noise: it usually indicates the address was already removed or the link is already gone.

Source

Thrown at proxy/tun/tun_linux.go:259

		if err != nil {
			_ = t.unsetInterfaceAddresses()
			return errors.New("invalid interface address ", address).Base(err)
		}
		if err := netlink.AddrAdd(t.tunLink, addr); err != nil {
			_ = t.unsetInterfaceAddresses()
			return errors.New("failed to add interface address ", address).Base(err)
		}
		t.interfaceAddresses = append(t.interfaceAddresses, *addr)
	}
	return nil
}

func (t *LinuxTun) unsetInterfaceAddresses() error {
	var errs []error
	for i := len(t.interfaceAddresses) - 1; i >= 0; i-- {
		address := t.interfaceAddresses[i]
		if err := netlink.AddrDel(t.tunLink, &address); err != nil {
			errs = append(errs, errors.New("failed to delete interface address ", address.String()).Base(err))
		}
	}
	t.interfaceAddresses = nil
	return errors.Combine(errs...)
}

func (t *LinuxTun) setSystemRoutes() error {
	if len(t.options.AutoSystemRoutingTable) == 0 {
		return nil
	}
	tunIndex := t.tunLink.Attrs().Index
	for _, cidr := range t.options.AutoSystemRoutingTable {
		prefix, err := netip.ParsePrefix(cidr)
		if err != nil {
			return errors.New("invalid system route ", cidr).Base(err)
		}
		prefix = prefix.Masked()
		_, ipNet, _ := net.ParseCIDR(prefix.String())

View on GitHub (pinned to 7d214f8b09)

Solutions

1. Treat as non-fatal if addresses are verified absent afterwards (`ip addr show <tun>`)
2. Avoid externally manipulating TUN addresses while Xray owns the device
3. Stop Xray cleanly (SIGTERM) so its own teardown runs before any interface destruction

// cleanup errors are collected; treat combined error as non-fatal
if err := tun.Close(); err != nil {
	log.Warnf("tun cleanup: %v (verify with `ip addr show`)", err)
}

When it happens

Trigger: Another process (network manager, `ip addr flush`, a prior crash cleanup) removed the address first; the TUN link destroyed before teardown; addresses modified externally while Xray ran.

Common situations: System shutdown racing Xray shutdown; manual `ip addr flush dev tun0` while the proxy runs; repeated start/stop cycles where the kernel already reclaimed the ephemeral device.

Related errors

• invalid interface address {address}
• failed to add interface address {address}
• failed to delete system route
• failed to add system route {cidr}
• invalid xray.tun.fd: file descriptor is not a TUN device

AI-assisted analysis of XTLS/Xray-core@7d214f8b09 (2026-08-15). Data as JSON: /api/errors/6e50c7a4f119d9b0. Report an issue: GitHub.