diff --git a/cmd/build.go b/cmd/build.go
index 099d472..4617b86 100644
--- a/cmd/build.go
+++ b/cmd/build.go
@@ -71,7 +71,7 @@ func runBuild(args []string, wd string) {
 	defer gocBuild.Clean()
 	// doCover with original buildFlags, with new GOPATH( tmp:original )
 	// in the tmp directory
-	cover.Execute(buildFlags, gocBuild.NewGOPATH, gocBuild.TmpDir, mode, center)
+	cover.Execute(buildFlags, gocBuild.NewGOPATH, gocBuild.TmpDir, mode, agentPort, center)
 	// do install in the temporary directory
 	err = gocBuild.Build()
 	if err != nil {
diff --git a/cmd/commonflags.go b/cmd/commonflags.go
index e36647b..e48f7c9 100644
--- a/cmd/commonflags.go
+++ b/cmd/commonflags.go
@@ -9,6 +9,7 @@ var (
 	target     string
 	center     string
 	mode       string
+	agentPort  string
 	debugGoc   bool
 	buildFlags string
 
@@ -26,6 +27,7 @@ func addBasicFlags(cmdset *pflag.FlagSet) {
 func addCommonFlags(cmdset *pflag.FlagSet) {
 	addBasicFlags(cmdset)
 	cmdset.StringVar(&mode, "mode", "count", "coverage mode: set, count, atomic")
+	cmdset.StringVar(&agentPort, "agentport", "", "specify fixed port for registered service communicate with goc server. if not provided, using a random port")
 	cmdset.StringVar(&buildFlags, "buildflags", "", "specify the build flags")
 	// bind to viper
 	viper.BindPFlags(cmdset)
diff --git a/cmd/cover.go b/cmd/cover.go
index a9ae61c..d394980 100644
--- a/cmd/cover.go
+++ b/cmd/cover.go
@@ -48,7 +48,7 @@ goc cover --center=http://127.0.0.1:7777 --target=/path/to/target --mode=atomic
 			log.Fatalf("unknown -mode %v", mode)
 		}
 
-		cover.Execute(buildFlags, "", target, mode, center)
+		cover.Execute(buildFlags, "", target, mode, agentPort, center)
 	},
 }
 
diff --git a/cmd/install.go b/cmd/install.go
index 4dc48b9..dbe1f7a 100644
--- a/cmd/install.go
+++ b/cmd/install.go
@@ -64,7 +64,7 @@ func runInstall(args []string, wd string) {
 	defer gocBuild.Clean()
 	// doCover with original buildFlags, with new GOPATH( tmp:original )
 	// in the tmp directory
-	cover.Execute(buildFlags, gocBuild.NewGOPATH, gocBuild.TmpDir, mode, center)
+	cover.Execute(buildFlags, gocBuild.NewGOPATH, gocBuild.TmpDir, mode, agentPort, center)
 	// do install in the temporary directory
 	err = gocBuild.Install()
 	if err != nil {
diff --git a/cmd/run.go b/cmd/run.go
index f3ac9fb..99a8368 100644
--- a/cmd/run.go
+++ b/cmd/run.go
@@ -60,7 +60,7 @@ goc run . [--buildflags] [--exec] [--arguments]
 		fmt.Printf("[goc] goc server started: %s \n", gocServer)
 
 		// execute covers for the target source with original buildFlags and new GOPATH( tmp:original )
-		cover.Execute(buildFlags, gocBuild.NewGOPATH, gocBuild.TmpDir, mode, gocServer)
+		cover.Execute(buildFlags, gocBuild.NewGOPATH, gocBuild.TmpDir, mode, "", gocServer)
 
 		if err := gocBuild.Run(); err != nil {
 			log.Fatalf("Fail to run: %v", err)
diff --git a/pkg/cover/cover.go b/pkg/cover/cover.go
index 688095f..3c97de5 100644
--- a/pkg/cover/cover.go
+++ b/pkg/cover/cover.go
@@ -46,6 +46,7 @@ var (
 // TestCover is a collection of all counters
 type TestCover struct {
 	Mode         string
+	AgentPort    string
 	Center       string // cover profile host center
 	MainPkgCover *PackageCover
 	DepsCover    []*PackageCover
@@ -120,7 +121,7 @@ type PackageError struct {
 }
 
 //Execute execute go tool cover for all the .go files in the target folder
-func Execute(args, newGopath, target, mode, center string) error {
+func Execute(args, newGopath, target, mode, agentPort, center string) error {
 	if !isDirExist(target) {
 		log.Errorf("Target directory %s not exist", target)
 		return ErrCoverPkgFailed
@@ -152,6 +153,7 @@ func Execute(args, newGopath, target, mode, center string) error {
 			// new a testcover for this service
 			tc := TestCover{
 				Mode:         mode,
+				AgentPort:    agentPort,
 				Center:       center,
 				MainPkgCover: mainCover,
 			}
diff --git a/pkg/cover/cover_test.go b/pkg/cover/cover_test.go
index 098cc67..7bf1549 100644
--- a/pkg/cover/cover_test.go
+++ b/pkg/cover/cover_test.go
@@ -316,7 +316,7 @@ func TestExecuteForSimpleModProject(t *testing.T) {
 	testDir := filepath.Join(os.TempDir(), "goc-build-test")
 	copy.Copy(workingDir, testDir)
 
-	Execute("", gopath, testDir, "count", "http://127.0.0.1:7777")
+	Execute("", gopath, testDir, "count", "", "http://127.0.0.1:7777")
 
 	_, err := os.Lstat(filepath.Join(testDir, "http_cover_apis_auto_generated.go"))
 	if !assert.Equal(t, err, nil) {
diff --git a/pkg/cover/instrument.go b/pkg/cover/instrument.go
index ab4d396..4248d85 100644
--- a/pkg/cover/instrument.go
+++ b/pkg/cover/instrument.go
@@ -260,8 +260,12 @@ func listen() (ln net.Listener, host string, err error) {
 			return
 		}
 	}
-
-	ln, err = net.Listen("tcp4", ":0")
+	agentPort := "{{.AgentPort }}"
+	if agentPort != "" {
+		ln, err = net.Listen("tcp4", agentPort)
+	} else {
+		ln, err = net.Listen("tcp4", ":0")
+	}
 	if err != nil {
 		return
 	}