The current iteration of HTTP standard has a separate document on caching alone, which is about 30 pages long. It illustrates the growing complexity of HTTP beyond its apparent simplicity.
failregex = ^<HOST> -.*GET.*(\.php|\.asp|\.exe|\.pl|\.cgi|\.scgi) ^<HOST> -.*(wp-login|xmlrpc).*php.*^<HOST> -.*(HTTP/1\\.1|HTTP/1\\.0|HTTP/2).*(404|403|400).*$ This regular expression may be too broad or improperly formatted.