I am trying to limit the file types that can be proxied from our backend server. I am trying to limit it to jpg, gif, png, css and then two other specific files - Thumbnail.ashx and hearbeat.htm. I am also hoping to limit access to only certain referers.

I have tried this code which works fine for the jpg, gif, png, css but is not working for the heartbeat.htm file. It gives a 404 on all .htm files including heartbeat.htm.

location ~* (\.jpg|\.png|\.gif|\.css|ThumbNail\.ashx|heartbeat\.htm)$ {

valid_referers
none
blocked
example.com
www.example.com
examplellimages.com
www.examplellimages.com
1.examplellimages.com
2.examplellimages.com
3.examplellimages.com
4.examplellimages.com;

if ($invalid_referer) {
return 404;
}



proxy_pass http://exampleimages_com;
}

Any help would be appreciated.