How to enable "keep-alive" for all sites in multisite WP

Those are web server configurations, not set in WP. By default most webserver have the keepalive settings on.

Thank’s for the comment. I checked .htaccess and keep-alive is turned on, so home come that according to webpagetest.org the other site has keep-alive switched? Is there any way to debug this issue?

Subdomains, subfolders, or mapped domains?

Im not using mapped domains. Its multisite where both sites are installed under public_html and sharing the same wp folders. Maybe some other idea?

What KeepAlive settings are you using in .htaccess? FYI KeepAlive and KeepAliveTimeout directives can not be set in .htaccess; they will be ignored. People report that this setting works in .htaccess:

<ifModule mod_headers.c>
Header set Connection keep-alive
</ifModule>

This setting is what I have in .htaccess under /public_html.

Its multisite where both sites are installed under public_html and sharing the same wp folders. Maybe some other idea?

What are your URLs like?

domain.com/sitename (aka subfolder)

or

sitename.domain.com (aka subdomain)

OR

mappeddomain.com (aka mapped domains)

That’s what I was asking ??

I see ??
Well it’s just:
domain1.com and
domain2.com
Hope i was correct, no subdomain or subfolder at least.

I also made a step further. Found out with Firefox that on the second page, the connection is denoted: “keep-alive, close”. Also found this useful link:

on stack exchange

Hope i was correct, no subdomain or subfolder at least.

I don’t think you know what your site is running. Multisite is either subdomains or sub folders, and you use a plugin to map domains. Are you sure you’re even on a multisite network?

I think so:
define( ‘WP_ALLOW_MULTISITE’, true );

I guess it’s then subfolders and am not using any plugin to map domains.