--- a/testing/marionette/client/marionette_driver/transport.py
+++ b/testing/marionette/client/marionette_driver/transport.py
@@ -279,22 +279,30 @@ class TcpTransport(object):
         to come back.
         """
         self.last_id = self.last_id + 1
         cmd = Command(self.last_id, name, params)
         self.send(cmd)
         return self.receive()
 
     def close(self):
-        """Close the socket."""
+        """Close the socket.
+
+        First forces the socket to not send data anymore, and then explicitly
+        close it to free up its resources.
+
+        See: https://docs.python.org/2/howto/sockets.html#disconnecting
+        """
         if self.sock:
             try:
                 self.sock.shutdown(socket.SHUT_RDWR)
             except IOError as exc:
-                # Errno 57 is "socket not connected", which we don't care about here.
-                if exc.errno != 57:
+                # If the socket is already closed, don't care about:
+                #   Errno  57: Socket not connected
+                #   Errno 107: Transport endpoint is not connected
+                if exc.errno not in (57, 107):
                     raise
 
             self.sock.close()
             self.sock = None
 
     def __del__(self):
         self.close()