What causes "unsupported address and port strategy: " in XTLS/Xray-core?

unsupported address and port strategy:

Error message

unsupported address and port strategy:

What it means

Thrown while building SocketConfig when the 'addressPortStrategy' string inside 'sockopt' does not match any supported value. Accepted values (lowercase, as handled by the switch) include srvportonly, srvaddressonly, srvportandaddress, txtportonly, txtaddressonly, txtportandaddress (plus the other branches above the shown region). Any other string hits the default branch and fails the whole config build.

Source

Thrown at infra/conf/transport_sockopt.go:154

	addressPortStrategy := internet.AddressPortStrategy_None
	switch strings.ToLower(c.AddressPortStrategy) {
	case "none", "":
		addressPortStrategy = internet.AddressPortStrategy_None
	case "srvportonly":
		addressPortStrategy = internet.AddressPortStrategy_SrvPortOnly
	case "srvaddressonly":
		addressPortStrategy = internet.AddressPortStrategy_SrvAddressOnly
	case "srvportandaddress":
		addressPortStrategy = internet.AddressPortStrategy_SrvPortAndAddress
	case "txtportonly":
		addressPortStrategy = internet.AddressPortStrategy_TxtPortOnly
	case "txtaddressonly":
		addressPortStrategy = internet.AddressPortStrategy_TxtAddressOnly
	case "txtportandaddress":
		addressPortStrategy = internet.AddressPortStrategy_TxtPortAndAddress
	default:
		return nil, errors.New("unsupported address and port strategy: ", c.AddressPortStrategy)
	}

	happyEyeballs := &internet.HappyEyeballsConfig{Interleave: 1, PrioritizeIpv6: false, TryDelayMs: 0, MaxConcurrentTry: 4}
	if c.HappyEyeballsSettings != nil {
		happyEyeballs.PrioritizeIpv6 = c.HappyEyeballsSettings.PrioritizeIPv6
		happyEyeballs.Interleave = c.HappyEyeballsSettings.Interleave
		happyEyeballs.TryDelayMs = c.HappyEyeballsSettings.TryDelayMs
		happyEyeballs.MaxConcurrentTry = c.HappyEyeballsSettings.MaxConcurrentTry
	}

	return &internet.SocketConfig{
		Mark:                 c.Mark,
		Tfo:                  tfo,
		Tproxy:               tproxy,
		DomainStrategy:       dStrategy,
		AcceptProxyProtocol:  c.AcceptProxyProtocol,
		DialerProxy:          c.DialerProxy,
		TcpKeepAliveInterval: c.TCPKeepAliveInterval,

View on GitHub (pinned to 7d214f8b09)

Solutions

Use an exact literal: "srvportonly", "srvaddressonly", "srvportandaddress", "txtportonly", "txtaddressonly", "txtportandaddress" (lowercase)
Remove the addressPortStrategy key if SRV/TXT-based resolution is not intended

Example fix

// before
"sockopt": { "addressPortStrategy": "SrvPortOnly" }
// after
"sockopt": { "addressPortStrategy": "srvportonly" }

Defensive patterns

Strategy: validation

Validate before calling

var addressPortStrategies = map[string]bool{
    "": true, "srvportonly": true, "srvaddressonly": true, "srvportandaddress": true,
    "txtportonly": true, "txtaddressonly": true, "txtportandaddress": true,
}
if s, ok := sockopt["addressPortStrategy"]; ok {
    if !addressPortStrategies[s.(string)] {
        return fmt.Errorf("invalid sockopt.addressPortStrategy: %q", s)
    }
}

Prevention

Copy the exact lowercase literal from the Xray docs
Add a lint step that checks enum-like strings against allow-lists

When it happens

Trigger: Setting "sockopt": { "addressPortStrategy": "srv" }, "SrvPortOnly" (wrong case), or "txt" in streamSettings, then starting Xray or reloading config.

Common situations: Guessing/abbreviating the strategy name instead of copying the documented literal, using uppercase from documentation prose, or trailing spaces from copy-paste.

Related errors

AI-assisted analysis of XTLS/Xray-core@7d214f8b09 (2026-08-15). Data as JSON: /api/errors/e9cbea895171cb78. Report an issue: GitHub.