Ok, let me introduce PROUDNET!

ProudNet is high-powered engine designed to handle high network traffic and a large number of simultaneous users with stability and robustness.

It is also included mobile version of game server engine, so you don’t need to purchase mobile version separately.
Many game developers in worldwide proved and used(are using) ProudNet and the numbers are getting larger.

You can code racing, action, air combat, fps, mmorpg games and social network games as well.
Also many of the well-known game company, Nexon, Gravity, CCR are already using ProudNet.

As you know, you might not sure to know this if you don’t use it. So I propose that you use free download, it is FREE!
Here is the link, http://www.nettention.com/request/. 
To get more information and benefits, put FASTech at the last answer, then all set!

Here’s the website,
Nettention : http://www.nettention.com/

For more information, please feel free to contact me, [email protected].