diff --git a/main.go b/main.go
index e7cace9..4c1cfce 100644
--- a/main.go
+++ b/main.go
@@ -112,10 +112,8 @@ func init() {
 		panic(err)
 	}
 
-	_state.OnGatewayPortChange(func(s string) error {
-		config.Set(common.ConfigKeyGatewayPort, _state.GetGatewayPort())
-		config.Set(common.ConfigKeyRuntimePath, _state.GetRuntimePath())
-
+	_state.OnGatewayPortChange(func(port string) error {
+		config.Set(common.ConfigKeyGatewayPort, port)
 		return config.WriteConfig()
 	})
 }
diff --git a/route/management_route_test.go b/route/management_route_test.go
index df9c944..0698e52 100644
--- a/route/management_route_test.go
+++ b/route/management_route_test.go
@@ -3,6 +3,7 @@ package route
 import (
 	"bytes"
 	"encoding/json"
+	"errors"
 	"net/http"
 	"net/http/httptest"
 	"os"
@@ -134,3 +135,75 @@ func TestChangePort(t *testing.T) {
 	assert.NilError(t, err)
 	assert.Equal(t, expectedPort, result.Data)
 }
+
+func TestChangePortNegative(t *testing.T) {
+	defer setup(t)(t)
+
+	expectedPort := "123"
+
+	// set
+	request := &model.ChangePortRequest{
+		Port: expectedPort,
+	}
+
+	body, err := json.Marshal(request)
+	assert.NilError(t, err)
+
+	req, _ := http.NewRequest(http.MethodPut, "/v1/gateway/port", bytes.NewReader(body))
+	req.RemoteAddr = "127.0.0.1:0"
+
+	w := httptest.NewRecorder()
+	_router.ServeHTTP(w, req)
+
+	assert.Equal(t, http.StatusOK, w.Code)
+	assert.Equal(t, expectedPort, "123")
+
+	// get
+	req, _ = http.NewRequest(http.MethodGet, "/v1/gateway/port", nil)
+
+	w = httptest.NewRecorder()
+	_router.ServeHTTP(w, req)
+
+	assert.Equal(t, http.StatusOK, w.Code)
+
+	var result *model.Result
+	decoder := json.NewDecoder(w.Body)
+
+	err = decoder.Decode(&result)
+	assert.NilError(t, err)
+	assert.Equal(t, expectedPort, result.Data)
+
+	// emulate error
+	_state.OnGatewayPortChange(func(_ string) error {
+		return errors.New("error")
+	})
+
+	// set
+	request.Port = "456"
+
+	body, err = json.Marshal(request)
+	assert.NilError(t, err)
+
+	req, _ = http.NewRequest(http.MethodPut, "/v1/gateway/port", bytes.NewReader(body))
+	req.RemoteAddr = "127.0.0.1:0"
+
+	w = httptest.NewRecorder()
+	_router.ServeHTTP(w, req)
+
+	assert.Equal(t, http.StatusInternalServerError, w.Code)
+	assert.Equal(t, expectedPort, "123")
+
+	// get
+	req, _ = http.NewRequest(http.MethodGet, "/v1/gateway/port", nil)
+
+	w = httptest.NewRecorder()
+	_router.ServeHTTP(w, req)
+
+	assert.Equal(t, http.StatusOK, w.Code)
+
+	decoder = json.NewDecoder(w.Body)
+
+	err = decoder.Decode(&result)
+	assert.NilError(t, err)
+	assert.Equal(t, expectedPort, result.Data)
+}
diff --git a/service/state.go b/service/state.go
index 7f09dce..78b7bb9 100644
--- a/service/state.go
+++ b/service/state.go
@@ -18,9 +18,13 @@ func NewState() *State {
 	}
 }
 
-func (c *State) SetGatewayPort(port string) error {
-	c.gatewayPort = port
-	return c.notifyOnGatewayPortChange()
+func (c *State) SetGatewayPort(port string) (err error) {
+	defer func() {
+		if err == nil {
+			c.gatewayPort = port
+		}
+	}()
+	return c.notifyOnGatewayPortChange(port)
 }
 
 func (c *State) GetGatewayPort() string {
@@ -32,9 +36,9 @@ func (c *State) OnGatewayPortChange(f func(string) error) {
 	c.onGatewayPortChange = append(c.onGatewayPortChange, f)
 }
 
-func (c *State) notifyOnGatewayPortChange() error {
+func (c *State) notifyOnGatewayPortChange(port string) error {
 	for i := len(c.onGatewayPortChange) - 1; i >= 0; i-- {
-		if err := c.onGatewayPortChange[i](c.gatewayPort); err != nil {
+		if err := c.onGatewayPortChange[i](port); err != nil {
 			return err
 		}
 	}