diff --git a/src/main/java/core/packetproxy/PrivateDNS.java b/src/main/java/core/packetproxy/PrivateDNS.java
index 13f3bd9f..c849b2fc 100644
--- a/src/main/java/core/packetproxy/PrivateDNS.java
+++ b/src/main/java/core/packetproxy/PrivateDNS.java
@@ -149,7 +149,7 @@ public boolean isRunning() throws Exception {
 		return state.getState();
 	}
 
-	public void start(DNSSpoofingIPGetter dnsSpoofingIPGetter) {
+	public boolean start(DNSSpoofingIPGetter dnsSpoofingIPGetter) {
 		synchronized (lock) {
 			if (dns == null) {
 
@@ -162,16 +162,26 @@ public void start(DNSSpoofingIPGetter dnsSpoofingIPGetter) {
 						state.setState(true);
 					} else {
 
+						dns = null;
+						state.setState(false);
+						return false;
 					}
 				} catch (Exception e) {
 
 					errWithStackTrace(e);
+					dns = null;
+					try {
+						state.setState(false);
+					} catch (Exception ignored) {
+					}
+					return false;
 				}
 			}
 		}
+		return true;
 	}
 
-	public void restart(DNSSpoofingIPGetter dnsSpoofingIPGetter) {
+	public boolean restart(DNSSpoofingIPGetter dnsSpoofingIPGetter) {
 		synchronized (lock) {
 			if (dns != null) {
 
@@ -190,12 +200,20 @@ public void restart(DNSSpoofingIPGetter dnsSpoofingIPGetter) {
 
 					dns = null;
 					state.setState(false);
+					return false;
 				}
 			} catch (Exception e) {
 
 				errWithStackTrace(e);
+				dns = null;
+				try {
+					state.setState(false);
+				} catch (Exception ignored) {
+				}
+				return false;
 			}
 		}
+		return true;
 	}
 
 	public int getConfiguredPort() {
@@ -236,8 +254,8 @@ public void setPort(int port, DNSSpoofingIPGetter dnsSpoofingIPGetter) {
 		}
 
 		try {
-			if (isRunning()) {
-				restart(dnsSpoofingIPGetter);
+			if (isRunning() && !restart(dnsSpoofingIPGetter)) {
+				state.setState(false);
 			}
 		} catch (Exception e) {
 			errWithStackTrace(e);
diff --git a/src/main/java/core/packetproxy/gui/GUIOptionPrivateDNS.java b/src/main/java/core/packetproxy/gui/GUIOptionPrivateDNS.java
index 7d19bb5c..fb1d85e9 100644
--- a/src/main/java/core/packetproxy/gui/GUIOptionPrivateDNS.java
+++ b/src/main/java/core/packetproxy/gui/GUIOptionPrivateDNS.java
@@ -42,6 +42,7 @@
 import javax.swing.JComboBox;
 import javax.swing.JComponent;
 import javax.swing.JLabel;
+import javax.swing.JOptionPane;
 import javax.swing.JPanel;
 import javax.swing.JRadioButton;
 import javax.swing.JTextField;
@@ -384,10 +385,15 @@ public String getSpoofingIP6() {
 	private JCheckBox createCheckBox() {
 		checkBox = new JCheckBox(I18nString.get("Use private DNS server"));
 		checkBox.addActionListener(e -> {
-			if (checkBox.isSelected())
-				privateDNS.start(new DNSSpoofingIPGetter(this));
-			else
+			if (!checkBox.isSelected()) {
 				privateDNS.stop();
+				return;
+			}
+
+			if (!privateDNS.start(new DNSSpoofingIPGetter(this))) {
+				checkBox.setSelected(false);
+				showPrivateDnsStartErrorDialog();
+			}
 		});
 		checkBox.setMinimumSize(new Dimension(Short.MAX_VALUE, checkBox.getMaximumSize().height));
 		return checkBox;
@@ -428,8 +434,13 @@ public void updateState() {
 
 			checkBox.setSelected(new ConfigBoolean("PrivateDNS").getState());
 			updateDnsPortFieldText(Integer.toString(privateDNS.getConfiguredPort()));
-			if (checkBox.isSelected())
-				privateDNS.start(new DNSSpoofingIPGetter(this));
+			if (!checkBox.isSelected()) {
+				return;
+			}
+			if (!privateDNS.start(new DNSSpoofingIPGetter(this))) {
+				checkBox.setSelected(false);
+				showPrivateDnsStartErrorDialog();
+			}
 		} catch (Exception e) {
 
 			errWithStackTrace(e);
@@ -493,12 +504,20 @@ private void restartPrivateDnsForBindingInterfaceChange() {
 			if (!privateDNS.isRunning()) {
 				return;
 			}
-			privateDNS.restart(new DNSSpoofingIPGetter(this));
+			if (!privateDNS.restart(new DNSSpoofingIPGetter(this))) {
+				checkBox.setSelected(false);
+				showPrivateDnsStartErrorDialog();
+			}
 		} catch (Exception e) {
 			errWithStackTrace(e);
 		}
 	}
 
+	private void showPrivateDnsStartErrorDialog() {
+		var message = I18nString.get("Failed to start private DNS server. Please check permissions and listen port.");
+		JOptionPane.showMessageDialog(null, message, I18nString.get("Error"), JOptionPane.ERROR_MESSAGE);
+	}
+
 	@Override
 	public void propertyChange(PropertyChangeEvent evt) {
 		if (CONFIGS.matches(evt)) {
diff --git a/src/main/resources/strings_ja.properties b/src/main/resources/strings_ja.properties
index 934c2353..e4d4b995 100644
--- a/src/main/resources/strings_ja.properties
+++ b/src/main/resources/strings_ja.properties
@@ -142,6 +142,7 @@ Use_*_to_apply_all_ports=全てのポートに適用するために * が使え
 Use_SSL/TLS\:=SSL/TLSを利用:
 Use_private_DNS_server=プライベートDNSサーバを起動する
 Use_private_DNS_server_that_resolves_server_name_to_the_IP_address_of_this_pc.=サーバの名前を自分自身のIPアドレスに名前解決したいときに利用します
+Failed_to_start_private_DNS_server._Please_check_permissions_and_listen_port.=プライベートDNSサーバの起動に失敗しました。権限と待ち受けポートを確認してください。
 Use_OpenVPN_Server_as_Docker_Container_to_proxy_HTTP/HTTPS_without_DNS_Spoofing.=OpenVPNサーバをDocker Containerとして利用し、DNS Spoofingを用いずに通信を取得する
 will_be_used_for_VPN=をOpenVPNのプロトコルとして使います
 Use_OpenVPN=OpenVPNサーバを起動する