XTLS/Xray-core · error

unsupported domain strategy:

Error message

unsupported domain strategy: 

What it means

Thrown while building SocketConfig when the 'domainStrategy' string inside 'sockopt' does not match any supported value. The switch accepts only AsIs, UseIP, UseIPv4, UseIPv6, UseIP46, UseIP64, ForceIP, ForceIPv4, ForceIPv6, ForceIPv4v6, ForceIPv6v4 (case-sensitive as written in the source); anything else hits the default branch. Note this is the sockopt-level strategy, distinct from the top-level outbound 'domainStrategy'.

Source

Thrown at infra/conf/transport_sockopt.go:120

		dStrategy = internet.DomainStrategy_USE_IP4
	case "useipv6":
		dStrategy = internet.DomainStrategy_USE_IP6
	case "useipv4v6":
		dStrategy = internet.DomainStrategy_USE_IP46
	case "useipv6v4":
		dStrategy = internet.DomainStrategy_USE_IP64
	case "forceip":
		dStrategy = internet.DomainStrategy_FORCE_IP
	case "forceipv4":
		dStrategy = internet.DomainStrategy_FORCE_IP4
	case "forceipv6":
		dStrategy = internet.DomainStrategy_FORCE_IP6
	case "forceipv4v6":
		dStrategy = internet.DomainStrategy_FORCE_IP46
	case "forceipv6v4":
		dStrategy = internet.DomainStrategy_FORCE_IP64
	default:
		return nil, errors.New("unsupported domain strategy: ", c.DomainStrategy)
	}

	var customSockopts []*internet.CustomSockopt

	for _, copt := range c.CustomSockopt {
		customSockopt := &internet.CustomSockopt{
			System:  copt.Syetem,
			Network: copt.Network,
			Level:   copt.Level,
			Opt:     copt.Opt,
			Value:   copt.Value,
			Type:    copt.Type,
		}
		customSockopts = append(customSockopts, customSockopt)
	}

	addressPortStrategy := internet.AddressPortStrategy_None
	switch strings.ToLower(c.AddressPortStrategy) {

View on GitHub (pinned to 7d214f8b09)

Solutions

1. Use one of the exact camelCase values: "AsIs", "UseIP", "UseIPv4", "UseIPv6", "UseIP46", "UseIP64", "ForceIP", "ForceIPv4", "ForceIPv6", "ForceIPv4v6", "ForceIPv6v4"
2. Check for typos and stray whitespace in the value
3. Remove the key to fall back to the default behavior if sockopt-level domain strategy is not required

Example fix

// before
"sockopt": { "domainStrategy": "use-ipv4" }
// after
"sockopt": { "domainStrategy": "UseIPv4" }

var sockoptDomainStrategies = map[string]bool{
    "AsIs": true, "UseIP": true, "UseIPv4": true, "UseIPv6": true,
    "UseIP46": true, "UseIP64": true, "ForceIP": true, "ForceIPv4": true,
    "ForceIPv6": true, "ForceIPv4v6": true, "ForceIPv6v4": true,
}
if s, ok := sockopt["domainStrategy"]; ok {
    if !sockoptDomainStrategies[s.(string)] {
        return fmt.Errorf("invalid sockopt.domainStrategy: %q", s)
    }
}

When it happens

Trigger: Setting "sockopt": { "domainStrategy": "use-ip" } (kebab-case), "Use_IP", "Asis", or a typo like "UzeIP" in streamSettings of any inbound/outbound.

Common situations: Mixing up casing conventions with other Xray fields that are case-insensitive, porting a V2Ray config that used different spellings, or assuming kebab-case like the DNS strategy names.

Related errors

• unsupported address and port strategy:
• Unable to locate a fake DNS Engine
• failed to parse name server: {}
• nameserver address is not specified
• not an IP address:{}

AI-assisted analysis of XTLS/Xray-core@7d214f8b09 (2026-08-15). Data as JSON: /api/errors/2bf61d58082115ab. Report an issue: GitHub.