XTLS/Xray-core · error

unable to set ips

Error message

unable to set ips

What it means

On Windows, after routes are set, gateway addresses are applied via LUID.SetIPAddresses. Failure wraps into this error. Note the addresses are built with netip.MustParsePrefix, so invalid gateway strings panic rather than reach this error; this error specifically means the winipcfg call itself failed — usually privileges, an invalid address family for the adapter, or the adapter disappearing.

Source

Thrown at proxy/tun/tun_windows.go:126

	}
	routesData := make([]*winipcfg.RouteData, 0, len(routesMap))
	for route := range routesMap {
		r := route
		routesData = append(routesData, &r)
	}
	err := t.luid.SetRoutes(routesData)
	if err != nil {
		return errors.New("unable to set routes").Base(err)
	}

	if len(t.options.Gateway) > 0 {
		addresses := make([]netip.Prefix, 0, len(t.options.Gateway))
		for _, address := range t.options.Gateway {
			addresses = append(addresses, netip.MustParsePrefix(address))
		}
		err := t.luid.SetIPAddresses(addresses)
		if err != nil {
			return errors.New("unable to set ips").Base(err)
		}
	}

	if has4 {
		ipif, err := t.luid.IPInterface(windows.AF_INET)
		if err != nil {
			return err
		}
		ipif.RouterDiscoveryBehavior = winipcfg.RouterDiscoveryDisabled
		ipif.DadTransmits = 0
		ipif.ManagedAddressConfigurationSupported = false
		ipif.OtherStatefulConfigurationSupported = false
		ipif.NLMTU = t.options.MTU
		ipif.UseAutomaticMetric = false
		ipif.Metric = 0
		err = ipif.Set()
		if err != nil {
			return err

View on GitHub (pinned to 7d214f8b09)

Solutions

1. Run elevated (Administrator/SYSTEM)
2. Ensure gateway prefixes are valid and match enabled address families
3. Remove addresses other tools put on the adapter, or stop those tools
4. Enable IPv6 components if using IPv6 gateway prefixes

Example fix

// before
"gateway": ["172.19.0.1/30", "fd00::1/128"]  // system IPv6 disabled

// after
"gateway": ["172.19.0.1/30"]

for _, gw := range cfg.Gateway {
	if _, err := netip.ParsePrefix(gw); err != nil {
		log.Fatalf("invalid gateway %q (must be valid prefix; invalid values panic)", gw)
	}
}

When it happens

Trigger: Non-elevated process; mixing IPv4 and IPv6 gateway prefixes when the adapter has only one family enabled; adapter removed/racing during setup; duplicate address already assigned by another process.

Common situations: Running without admin rights; IPv6 disabled system-wide but IPv6 gateways configured; another service (ICS, VPN) assigning addresses to the adapter.

Related errors

• unable to set routes
• failed to add interface address {address}
• invalid interface address {address}
• failed to delete interface address {address}
• failed to add system route {cidr}

AI-assisted analysis of XTLS/Xray-core@7d214f8b09 (2026-08-15). Data as JSON: /api/errors/59f0243519a20595. Report an issue: GitHub.