Enable Keep Alive
There are two options for enabling Keep Alive on Apache.
Via your Apache configuration file on your server; simply add:
You can ask your webhost if they can do this for you. Your server will have to be re-started after adding this.
Via your .htaccess file; add the following:
<ifModule mod_headers.c> Header set Connection keep-alive </ifModule>
If you use NGINX, Keep Alive should be on unless you find the following in your config file:
You can use these to tweak your settings:
Learn more: NGINX—Module ngx_http_core_module