For reasons known, server connections overseas Chinese mainland will be disturbed, so I use Haproxy reverse proxy it  in Hong Kong.
    I encountered such a problem, if the ssh connection idle for 50 seconds will automatically disconnect. I connect to the server and mainland China does not have this problem. So I think it is not Haproxy problem, I checked the configuration and Debug, did not find any problems.
  Well, this question must be in the SSH, I think. I tried this configuration:

TCPKeepAlive yes  
ClientAliveInterval 40  
ClientAliveCountMax 360  

```Then restart the SSH service, I connected again, never disconnect, and it works very well.