diff --git a/gui/default/assets/lang/lang-en.json b/gui/default/assets/lang/lang-en.json
index b7f1333f..dc350889 100644
--- a/gui/default/assets/lang/lang-en.json
+++ b/gui/default/assets/lang/lang-en.json
@@ -69,6 +69,7 @@
    "Enable NAT traversal": "Enable NAT traversal",
    "Enable Relaying": "Enable Relaying",
    "Enter a non-negative number (e.g., \"2.35\") and select a unit. Percentages are as part of the total disk size.": "Enter a non-negative number (e.g., \"2.35\") and select a unit. Percentages are as part of the total disk size.",
+   "Enter a non-privileged port number (1024 - 65535).": "Enter a non-privileged port number (1024 - 65535).",
    "Enter comma separated  (\"tcp://ip:port\", \"tcp://host:port\") addresses or \"dynamic\" to perform automatic discovery of the address.": "Enter comma separated  (\"tcp://ip:port\", \"tcp://host:port\") addresses or \"dynamic\" to perform automatic discovery of the address.",
    "Enter ignore patterns, one per line.": "Enter ignore patterns, one per line.",
    "Error": "Error",
@@ -92,6 +93,7 @@
    "GUI": "GUI",
    "GUI Authentication Password": "GUI Authentication Password",
    "GUI Authentication User": "GUI Authentication User",
+   "GUI Listen Address": "GUI Listen Address",
    "GUI Listen Addresses": "GUI Listen Addresses",
    "GUI Theme": "GUI Theme",
    "Generate": "Generate",
diff --git a/gui/default/syncthing/settings/settingsModalView.html b/gui/default/syncthing/settings/settingsModalView.html
index 88f5b567..51c1d593 100644
--- a/gui/default/syncthing/settings/settingsModalView.html
+++ b/gui/default/syncthing/settings/settingsModalView.html
@@ -100,9 +100,12 @@
         </div>
 
         <div class="col-md-6">
-          <div class="form-group">
-            <label translate for="Address">GUI Listen Addresses</label>
-            <input id="Address" class="form-control" type="text" ng-model="tmpGUI.address">
+          <div class="form-group"  ng-class="{'has-error': settingsEditor.Address.$invalid && settingsEditor.Address.$dirty}">
+            <label translate for="Address">GUI Listen Address</label>&emsp;<a href="https://docs.syncthing.net/users/guilisten.html" target="_blank"><span class="fa fa-fw fa-book"></span>&nbsp;<span translate>Help</span></a>
+            <input id="Address" name="Address" class="form-control" type="text" ng-model="tmpGUI.address" ng-pattern="/.*:0*((102[4-9])|(10[3-9][0-9])|(1[1-9][0-9][0-9])|([2-9][0-9][0-9][0-9])|([1-6]\d{4}))$/">
+              <p class="help-block" ng-show="settingsEditor.Address.$invalid" translate>
+                Enter a non-privileged port number (1024 - 65535).
+              </p>
           </div>
           <div class="form-group">
             <label translate for="User">GUI Authentication User</label>