diff --git a/websocket-sharp/Ext.cs b/websocket-sharp/Ext.cs
index 2ca1a666..67b93795 100644
--- a/websocket-sharp/Ext.cs
+++ b/websocket-sharp/Ext.cs
@@ -1538,8 +1538,13 @@ namespace WebSocketSharp
       var port = uri.Port;
       if (port > 0)
       {
-        if ((scheme == "ws"  && port == 443) ||
-            (scheme == "wss" && port == 80))
+        if (port > 65535)
+        {
+          message = "Invalid port number: " + port;
+          return false;
+        }
+
+        if ((scheme == "ws" && port == 443) || (scheme == "wss" && port == 80))
         {
           message = String.Format ("Invalid pair of scheme and port: {0}, {1}", scheme, port);
           return false;
diff --git a/websocket-sharp/Server/HttpServer.cs b/websocket-sharp/Server/HttpServer.cs
index dce9a5e7..d9f0c200 100644
--- a/websocket-sharp/Server/HttpServer.cs
+++ b/websocket-sharp/Server/HttpServer.cs
@@ -106,12 +106,13 @@ namespace WebSocketSharp.Server
       if (!port.IsPortNumber ())
         throw new ArgumentOutOfRangeException ("port", "Invalid port number: " + port);
 
-      if (port == 80 && secure || port == 443 && !secure)
+      if ((port == 80 && secure) || (port == 443 && !secure))
         throw new ArgumentException (String.Format (
           "Invalid pair of 'port' and 'secure': {0}, {1}", port, secure));
 
       _port = port;
       _secure = secure;
+
       init ();
     }
 
diff --git a/websocket-sharp/Server/WebSocketServerBase.cs b/websocket-sharp/Server/WebSocketServerBase.cs
index f1bea7a5..7b84faee 100644
--- a/websocket-sharp/Server/WebSocketServerBase.cs
+++ b/websocket-sharp/Server/WebSocketServerBase.cs
@@ -135,6 +135,9 @@ namespace WebSocketSharp.Server
     /// <exception cref="ArgumentNullException">
     /// Either <paramref name="address"/> or <paramref name="absPath"/> is <see langword="null"/>.
     /// </exception>
+    /// <exception cref="ArgumentOutOfRangeException">
+    /// <paramref name="port"/> is 0 or less, or 65536 or greater.
+    /// </exception>
     /// <exception cref="ArgumentException">
     ///   <para>
     ///   <paramref name="absPath"/> is invalid.
@@ -154,20 +157,19 @@ namespace WebSocketSharp.Server
       if (absPath == null)
         throw new ArgumentNullException ("absPath");
 
+      if (!port.IsPortNumber ())
+        throw new ArgumentOutOfRangeException ("port", "Invalid port number: " + port);
+
       string msg;
       if (!absPath.IsValidAbsolutePath (out msg))
         throw new ArgumentException (msg, "absPath");
 
-      if ((port == 80 && secure) ||
-          (port == 443 && !secure))
-      {
-        msg = String.Format (
-          "Invalid pair of 'port' and 'secure': {0}, {1}", port, secure);
-        throw new ArgumentException (msg);
-      }
+      if ((port == 80 && secure) || (port == 443 && !secure))
+        throw new ArgumentException (String.Format (
+          "Invalid pair of 'port' and 'secure': {0}, {1}", port, secure));
 
       _address = address;
-      _port = port > 0 ? port : secure ? 443 : 80;
+      _port = port;
       _uri = absPath.ToUri ();
       _secure = secure;
 
@@ -322,8 +324,9 @@ namespace WebSocketSharp.Server
 
       _uri = uri;
       _address = addrs [0];
+      _port = port;
       _secure = scheme == "wss" ? true : false;
-      _port = port > 0 ? port : _secure ? 443 : 80;
+
       init ();
     }