diff --git a/protocol/openconnect/endpoint.go b/protocol/openconnect/endpoint.go
index 21999365..b7915c61 100644
--- a/protocol/openconnect/endpoint.go
+++ b/protocol/openconnect/endpoint.go
@@ -4,7 +4,6 @@ import (
 	"context"
 	"net"
 	"net/netip"
-	"slices"
 	"strings"
 
 	"github.com/sagernet/sing-box/adapter"
@@ -33,10 +32,6 @@ type endpointBase struct {
 	logger log.ContextLogger
 }
 
-func (e *endpointBase) SupportsFlow(network string) bool {
-	return slices.Contains(e.Network(), network)
-}
-
 func (e *endpointBase) newConnection(ctx context.Context, endpoint adapter.Endpoint, localAddresses []netip.Prefix, conn net.Conn, source M.Socksaddr, destination M.Socksaddr, onClose N.CloseHandlerFunc) {
 	var metadata adapter.InboundContext
 	metadata.Inbound = endpoint.Tag()
diff --git a/protocol/openvpn/endpoint.go b/protocol/openvpn/endpoint.go
index 0aa7ff67..33cd43a1 100644
--- a/protocol/openvpn/endpoint.go
+++ b/protocol/openvpn/endpoint.go
@@ -38,10 +38,6 @@ type endpointBase struct {
 	logger log.ContextLogger
 }
 
-func (e *endpointBase) SupportsFlow(network string) bool {
-	return slices.Contains(e.Network(), network)
-}
-
 func (e *endpointBase) newConnection(ctx context.Context, endpoint adapter.Endpoint, localAddresses []netip.Prefix, conn net.Conn, source M.Socksaddr, destination M.Socksaddr, onClose N.CloseHandlerFunc) {
 	var metadata adapter.InboundContext
 	metadata.Inbound = endpoint.Tag()
diff --git a/protocol/tun/inbound.go b/protocol/tun/inbound.go
index 22172e50..719edd81 100644
--- a/protocol/tun/inbound.go
+++ b/protocol/tun/inbound.go
@@ -342,7 +342,7 @@ func (t *Inbound) Start(stage adapter.StartStage) error {
 			outboundManager := service.FromContext[adapter.OutboundManager](t.ctx)
 			endpointManager := service.FromContext[adapter.EndpointManager](t.ctx)
 			for _, outbound := range outboundManager.Outbounds() {
-				if _, isFlowOutbound := outbound.(adapter.FlowOutbound); isFlowOutbound && common.Contains(outbound.Network(), N.NetworkTCP) {
+				if flowOutbound, isFlowOutbound := outbound.(adapter.FlowOutbound); isFlowOutbound && flowOutbound.PreMatchFlow(N.NetworkTCP, netip.Addr{}) == adapter.PreMatchFlow {
 					if C.IsLinux {
 						t.tunOptions.GSO = true
 					} else {
@@ -352,7 +352,7 @@ func (t *Inbound) Start(stage adapter.StartStage) error {
 				}
 			}
 			for _, endpoint := range endpointManager.Endpoints() {
-				if _, isFlowOutbound := endpoint.(adapter.FlowOutbound); isFlowOutbound && common.Contains(endpoint.Network(), N.NetworkTCP) {
+				if flowOutbound, isFlowOutbound := endpoint.(adapter.FlowOutbound); isFlowOutbound && flowOutbound.PreMatchFlow(N.NetworkTCP, netip.Addr{}) == adapter.PreMatchFlow {
 					if C.IsLinux {
 						t.tunOptions.GSO = true
 					} else {