Limit the ports used by IT2Me when NAT traversal is disabled.

remoting/host/network_settings.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef REMOTING_HOST_NETWORK_SETTINGS_H_
 #define REMOTING_HOST_NETWORK_SETTINGS_H_
 
 namespace remoting {
 
 struct NetworkSettings {
+
+  // When hosts are configured with NAT traversal disabled they will
+  // typically also limit their P2P ports to this range, so that
+  // sessions may be blocked or un-blocked via firewall rules.
+  static const int kDefaultMinPort = 12400;
+  static const int kDefaultMaxPort = 12409;
+
   enum NatTraversalMode {
     // Active NAT traversal using STUN and relay servers.
     NAT_TRAVERSAL_ENABLED,
 
     // Don't use STUN or relay servers. Accept incoming P2P connection
     // attempts, but don't initiate any. This ensures that the peer is
     // on the same network. Note that connection will always fail if
     // both ends use this mode.
     NAT_TRAVERSAL_DISABLED,
 
@@ skipping 17 matching lines @@
 
   // |min_port| and |max_port| specify range (inclusive) of ports used by
   // P2P sessions. Any port can be used when both values are set to 0.
   int min_port;
   int max_port;
 };
 
 }  // namespace remoting
 
 #endif  // REMOTING_HOST_NETWORK_SETTINGS_H_