varnish
How to change varnish port in Ubuntu
To clear cache, run
/usr/bin/varnishadm -S /etc/varnish/secret -T 127.0.0.1:6082 "ban req.http.host ~ .*"
Get stats
varnishstat
See Varnish logs
varnishlog
To view logs for “Error 503 Service Unavailable” error.
varnishlog -q 'RespStatus == 503' -g request
mod_rpaf help with showing users real IP when site is behind a proxy or varnish.