If your backend is sensitive to keepalive traffic (mine are), then my
advice is to enable keepalives as far into your stack as you can.
i.e. I have nginx fronting haproxy and varnish, I enable keepalives to
both
haproxy and varnish add have them add a “connection: close” header to
their
backend requests. That keeps the backends happy but still lets the
frontends take advantage of connection reuse.