Keep-Alive for 20 secs

   The Keep-Alive general header allows the sender to hint about how the connection may be used to set a timeout and a maximum amount of requests.

Nginx

   Nginx is a web server which can also be used as a reverse proxy, load balancer, mail proxy and HTTP cache. The software was created by Igor Sysoev and first publicly released in 2004. A company of the same name was founded in 2011 to provide support and Nginx plus paid software.