Update system_listener.go

transport/internet/system_listener.go

@@ -2,12 +2,12 @@ package internet
 
 import (
 	"context"
+	gonet "net"
 	"os"
 	"runtime"
 	"strconv"
 	"strings"
 	"syscall"
-	"time"
 
 	"github.com/pires/go-proxyproto"
 	"github.com/sagernet/sing/common/control"
@@ -88,7 +88,13 @@ func (dl *DefaultListener) Listen(ctx context.Context, addr net.Addr, sockopt *S
 		network = addr.Network()
 		address = addr.String()
 		lc.Control = getControlFunc(ctx, sockopt, dl.controllers)
-		lc.KeepAlive = time.Duration(-1)
+		lc.KeepAliveConfig = gonet.KeepAliveConfig{
+			// Set Enable to true but all other fields to -1 to use system defaults (see https://pkg.go.dev/net#KeepAliveConfig)
+			Enable:   true,
+			Idle:     -1,
+			Interval: -1,
+			Count:    -1,
+		}
 		if sockopt != nil {
 			if sockopt.TcpMptcp {
 				lc.SetMultipathTCP(true)