diff --git a/TechnitiumLibrary.Net/Proxy/TransparentProxyServer.cs b/TechnitiumLibrary.Net/Proxy/TransparentProxyServer.cs
index 8e44dcec..41cea14b 100644
--- a/TechnitiumLibrary.Net/Proxy/TransparentProxyServer.cs
+++ b/TechnitiumLibrary.Net/Proxy/TransparentProxyServer.cs
@@ -63,7 +63,7 @@ public TransparentProxyServer(IProxyServerConnectionManager connectionManager =
 
         public TransparentProxyServer(IPEndPoint localEP, IProxyServerConnectionManager connectionManager = null, TransparentProxyServerMethod method = TransparentProxyServerMethod.DNAT, int backlog = 10)
         {
-            if (_method != TransparentProxyServerMethod.Tunnel)
+            if (method != TransparentProxyServerMethod.Tunnel)
             {
                 if (Environment.OSVersion.Platform != PlatformID.Unix)
                     throw new NotSupportedException("Only Unix/Linux is supported.");