diff --git a/config/config.go b/config/config.go
index ac5f4a1e..39448b87 100644
--- a/config/config.go
+++ b/config/config.go
@@ -114,7 +114,7 @@ type Profile struct {
 type Tun struct {
 	Enable              bool             `yaml:"enable" json:"enable"`
 	Device              string           `yaml:"device" json:"device"`
-	Stack               string           `yaml:"stack" json:"stack"`
+	Stack               C.TUNStack       `yaml:"stack" json:"stack"`
 	DNSHijack           []netip.AddrPort `yaml:"dns-hijack" json:"dns-hijack"`
 	AutoRoute           bool             `yaml:"auto-route" json:"auto-route"`
 	AutoDetectInterface bool             `yaml:"auto-detect-interface" json:"auto-detect-interface"`
@@ -250,13 +250,13 @@ type RawFallbackFilter struct {
 }
 
 type RawTun struct {
-	Enable              bool     `yaml:"enable" json:"enable"`
-	Device              string   `yaml:"device" json:"device"`
-	Stack               string   `yaml:"stack" json:"stack"`
-	DNSHijack           []string `yaml:"dns-hijack" json:"dns-hijack"`
-	AutoRoute           bool     `yaml:"auto-route" json:"auto-route"`
-	AutoDetectInterface bool     `yaml:"auto-detect-interface"`
-	RedirectToTun       []string `yaml:"-" json:"-"`
+	Enable              bool       `yaml:"enable" json:"enable"`
+	Device              string     `yaml:"device" json:"device"`
+	Stack               C.TUNStack `yaml:"stack" json:"stack"`
+	DNSHijack           []string   `yaml:"dns-hijack" json:"dns-hijack"`
+	AutoRoute           bool       `yaml:"auto-route" json:"auto-route"`
+	AutoDetectInterface bool       `yaml:"auto-detect-interface"`
+	RedirectToTun       []string   `yaml:"-" json:"-"`
 
 	MTU uint32 `yaml:"mtu" json:"mtu,omitempty"`
 	//Inet4Address           []ListenPrefix `yaml:"inet4-address" json:"inet4_address,omitempty"`
@@ -371,7 +371,7 @@ func UnmarshalRawConfig(buf []byte) (*RawConfig, error) {
 		Tun: RawTun{
 			Enable:              false,
 			Device:              "",
-			Stack:               "gvisor",
+			Stack:               C.TunGvisor,
 			DNSHijack:           []string{"0.0.0.0:53"}, // default hijack all dns query
 			AutoRoute:           true,
 			AutoDetectInterface: true,
diff --git a/constant/tun.go b/constant/tun.go
index 10e24861..38f51155 100644
--- a/constant/tun.go
+++ b/constant/tun.go
@@ -7,13 +7,15 @@ import (
 )
 
 var StackTypeMapping = map[string]TUNStack{
-	strings.ToUpper(TunGvisor.String()): TunGvisor,
-	strings.ToUpper(TunSystem.String()): TunSystem,
+	strings.ToLower(TunGvisor.String()): TunGvisor,
+	strings.ToLower(TunSystem.String()): TunSystem,
+	strings.ToLower(TunLWIP.String()):   TunLWIP,
 }
 
 const (
 	TunGvisor TUNStack = iota
 	TunSystem
+	TunLWIP
 )
 
 type TUNStack int
@@ -24,7 +26,7 @@ func (e *TUNStack) UnmarshalYAML(unmarshal func(any) error) error {
 	if err := unmarshal(&tp); err != nil {
 		return err
 	}
-	mode, exist := StackTypeMapping[strings.ToUpper(tp)]
+	mode, exist := StackTypeMapping[strings.ToLower(tp)]
 	if !exist {
 		return errors.New("invalid tun stack")
 	}
@@ -41,7 +43,7 @@ func (e TUNStack) MarshalYAML() (any, error) {
 func (e *TUNStack) UnmarshalJSON(data []byte) error {
 	var tp string
 	json.Unmarshal(data, &tp)
-	mode, exist := StackTypeMapping[strings.ToUpper(tp)]
+	mode, exist := StackTypeMapping[strings.ToLower(tp)]
 	if !exist {
 		return errors.New("invalid tun stack")
 	}
@@ -60,6 +62,8 @@ func (e TUNStack) String() string {
 		return "gVisor"
 	case TunSystem:
 		return "System"
+	case TunLWIP:
+		return "LWIP"
 	default:
 		return "unknown"
 	}
diff --git a/listener/sing_tun/server.go b/listener/sing_tun/server.go
index ea173481..2e388440 100644
--- a/listener/sing_tun/server.go
+++ b/listener/sing_tun/server.go
@@ -186,7 +186,7 @@ func New(options config.Tun, tcpIn chan<- C.ConnContext, udpIn chan<- *inbound.P
 		return
 	}
 	l.tunIf = tunIf
-	l.tunStack, err = tun.NewStack(options.Stack, tun.StackOptions{
+	l.tunStack, err = tun.NewStack(strings.ToLower(options.Stack.String()), tun.StackOptions{
 		Context:                context.TODO(),
 		Tun:                    tunIf,
 		MTU:                    tunOptions.MTU,