diff --git a/app/src/main/java/io/nekohasekai/sagernet/bg/proto/TestInstance.kt b/app/src/main/java/io/nekohasekai/sagernet/bg/proto/TestInstance.kt
index ed7fc5a..57d1a17 100644
--- a/app/src/main/java/io/nekohasekai/sagernet/bg/proto/TestInstance.kt
+++ b/app/src/main/java/io/nekohasekai/sagernet/bg/proto/TestInstance.kt
@@ -12,7 +12,7 @@ import kotlinx.coroutines.delay
 import libcore.Libcore
 import kotlin.coroutines.suspendCoroutine
 
-class TestInstance(profile: ProxyEntity, val link: String, val timeout: Int) :
+class TestInstance(profile: ProxyEntity, val link: String, private val timeout: Int) :
     BoxInstance(profile) {
 
     suspend fun doTest(): Int {
diff --git a/app/src/main/java/io/nekohasekai/sagernet/bg/proto/UrlTest.kt b/app/src/main/java/io/nekohasekai/sagernet/bg/proto/UrlTest.kt
index 3cec7cf..73b6546 100644
--- a/app/src/main/java/io/nekohasekai/sagernet/bg/proto/UrlTest.kt
+++ b/app/src/main/java/io/nekohasekai/sagernet/bg/proto/UrlTest.kt
@@ -6,7 +6,7 @@ import io.nekohasekai.sagernet.database.ProxyEntity
 class UrlTest {
 
     val link = DataStore.connectionTestURL
-    val timeout = 3000
+    private val timeout = 5000
 
     suspend fun doTest(profile: ProxyEntity): Int {
         return TestInstance(profile, link, timeout).doTest()
diff --git a/app/src/main/java/io/nekohasekai/sagernet/fmt/ConfigBuilder.kt b/app/src/main/java/io/nekohasekai/sagernet/fmt/ConfigBuilder.kt
index 7ac3eec..64bd0b9 100644
--- a/app/src/main/java/io/nekohasekai/sagernet/fmt/ConfigBuilder.kt
+++ b/app/src/main/java/io/nekohasekai/sagernet/fmt/ConfigBuilder.kt
@@ -182,12 +182,6 @@ fun buildConfig(
         }
 
         dns = DNSOptions().apply {
-            // TODO nb4a hosts?
-//            hosts = DataStore.hosts.split("\n")
-//                .filter { it.isNotBlank() }
-//                .associate { it.substringBefore(" ") to it.substringAfter(" ") }
-//                .toMutableMap()
-
             servers = mutableListOf()
             rules = mutableListOf()
             independent_cache = true
@@ -665,7 +659,8 @@ fun buildConfig(
 
         // remote dns obj
         remoteDns.firstOrNull().let {
-            dns.servers.add(DNSServerOptions().apply {
+            // Always use direct DNS for urlTest
+            if (!forTest) dns.servers.add(DNSServerOptions().apply {
                 address = it ?: throw Exception("No remote DNS, check your settings!")
                 tag = "dns-remote"
                 address_resolver = "dns-direct"
@@ -701,8 +696,6 @@ fun buildConfig(
         }
 
         if (forTest) {
-            // Always use direct DNS for urlTest
-            dns.servers.removeAt(0)
             dns.rules = listOf()
         } else {
             // built-in DNS rules
diff --git a/app/src/main/java/io/nekohasekai/sagernet/ui/ConfigurationFragment.kt b/app/src/main/java/io/nekohasekai/sagernet/ui/ConfigurationFragment.kt
index ec53e1a..f9090d3 100644
--- a/app/src/main/java/io/nekohasekai/sagernet/ui/ConfigurationFragment.kt
+++ b/app/src/main/java/io/nekohasekai/sagernet/ui/ConfigurationFragment.kt
@@ -821,10 +821,6 @@ class ConfigurationFragment @JvmOverloads constructor(
         val testJobs = mutableListOf<Job>()
 
         val mainJob = runOnDefaultDispatcher {
-            if (DataStore.serviceState.started) {
-                stopService()
-                delay(500) // wait for service stop
-            }
             val group = DataStore.currentGroup()
             val profilesUnfiltered = SagerDatabase.proxyDao.getByGroup(group.id)
             test.proxyN = profilesUnfiltered.size
diff --git a/libcore/go.mod b/libcore/go.mod
index 57ee562..55f7308 100644
--- a/libcore/go.mod
+++ b/libcore/go.mod
@@ -14,6 +14,7 @@ require (
 	github.com/sagernet/sing-tun v0.6.1
 	github.com/ulikunitz/xz v0.5.11
 	golang.org/x/mobile v0.0.0-20231108233038-35478a0c49da
+	golang.org/x/sys v0.30.0
 )
 
 require (
@@ -78,7 +79,6 @@ require (
 	golang.org/x/mod v0.20.0 // indirect
 	golang.org/x/net v0.34.0 // indirect
 	golang.org/x/sync v0.10.0 // indirect
-	golang.org/x/sys v0.30.0 // indirect
 	golang.org/x/text v0.21.0 // indirect
 	golang.org/x/time v0.7.0 // indirect
 	golang.org/x/tools v0.24.0 // indirect
diff --git a/libcore/nb4a.go b/libcore/nb4a.go
index cad7d3d..d049dca 100644
--- a/libcore/nb4a.go
+++ b/libcore/nb4a.go
@@ -1,6 +1,7 @@
 package libcore
 
 import (
+	"fmt"
 	"libcore/device"
 	"os"
 	"path/filepath"
@@ -13,11 +14,14 @@ import (
 	"github.com/matsuridayo/libneko/neko_common"
 	"github.com/matsuridayo/libneko/neko_log"
 	"github.com/sagernet/sing-box/nekoutils"
+	"golang.org/x/sys/unix"
 )
 
 //go:linkname resourcePaths github.com/sagernet/sing-box/constant.resourcePaths
 var resourcePaths []string
 
+var isBgProcess bool
+
 func NekoLogPrintln(s string) {
 	log.Println(s)
 }
@@ -35,7 +39,7 @@ func InitCore(process, cachePath, internalAssets, externalAssets string,
 	if1 NB4AInterface, if2 BoxPlatformInterface,
 ) {
 	defer device.DeferPanicToError("InitCore", func(err error) { log.Println(err) })
-	isBgProcess := strings.HasSuffix(process, ":bg")
+	isBgProcess = strings.HasSuffix(process, ":bg")
 
 	neko_common.RunMode = neko_common.RunMode_NekoBoxForAndroid
 	intfNB4A = if1
@@ -81,3 +85,37 @@ func InitCore(process, cachePath, internalAssets, externalAssets string,
 		}
 	}()
 }
+
+func sendFdToProtect(fd int, path string) error {
+	socketFd, err := unix.Socket(unix.AF_UNIX, unix.SOCK_STREAM, 0)
+	if err != nil {
+		return fmt.Errorf("failed to create unix socket: %w", err)
+	}
+	defer unix.Close(socketFd)
+
+	var timeout unix.Timeval
+	timeout.Usec = 100 * 1000
+
+	_ = unix.SetsockoptTimeval(socketFd, unix.SOL_SOCKET, unix.SO_RCVTIMEO, &timeout)
+	_ = unix.SetsockoptTimeval(socketFd, unix.SOL_SOCKET, unix.SO_SNDTIMEO, &timeout)
+
+	err = unix.Connect(socketFd, &unix.SockaddrUnix{Name: path})
+	if err != nil {
+		return fmt.Errorf("failed to connect: %w", err)
+	}
+
+	err = unix.Sendmsg(socketFd, nil, unix.UnixRights(fd), nil, 0)
+	if err != nil {
+		return fmt.Errorf("failed to send: %w", err)
+	}
+
+	dummy := []byte{1}
+	n, err := unix.Read(socketFd, dummy)
+	if err != nil {
+		return fmt.Errorf("failed to receive: %w", err)
+	}
+	if n != 1 {
+		return fmt.Errorf("socket closed unexpectedly")
+	}
+	return nil
+}
diff --git a/libcore/platform_box.go b/libcore/platform_box.go
index d8b1348..7e7378c 100644
--- a/libcore/platform_box.go
+++ b/libcore/platform_box.go
@@ -44,7 +44,12 @@ func (w *boxPlatformInterfaceWrapper) UsePlatformAutoDetectInterfaceControl() bo
 }
 
 func (w *boxPlatformInterfaceWrapper) AutoDetectInterfaceControl(fd int) error {
-	// "protect"
+	// call protect_path
+	if !isBgProcess {
+		_ = sendFdToProtect(fd, "protect_path")
+		return nil
+	}
+	// bg process call VPNService
 	return intfBox.AutoDetectInterfaceControl(int32(fd))
 }