Error Pages Cache | NetDNA Support Site

Caching for Error Pages

Sometimes clients will notice that their error pages are being cached. Say one of their files was missing from the origin, and they re-uploaded it, but CDN is still returning their 404 page until the cache is fully purged. The reason behind this is that the 404 page happened to have a Cache Control Header. In the example below, a 404 page with a CCH which will be cached.

$ curl -I http://foobar.example.com/myimages/some_random_image.png
HTTP/1.1 404 Not Found
Server: nginx/1.0.11
Date: Thu, 26 Jan 2012 20:01:36 GMT
Content-Type: text/html;charset=utf-8
Connection: keep-alive
<strong>Cache-Control: public, max-age=24383317
Expires: Tue, 06 Dec 2012 17:33:42 GMT
Last-Modified: Sat, 01 Jan 2000 00:00:00 GMT</strong>
Content-Length: 1051

$ curl -I http://foobar.example.com/myimages/some_random_image.png

HTTP/1.1 404 Not Found

Server: nginx/1.0.11

Date: Thu, 26 Jan 2012 20:01:36 GMT

Content-Type: text/html;charset=utf-8

Connection: keep-alive

<strong>Cache-Control: public, max-age=24383317

Expires: Tue, 06 Dec 2012 17:33:42 GMT

Last-Modified: Sat, 01 Jan 2000 00:00:00 GMT</strong>

Content-Length: 1051

These bolded headers should not exist with error pages, otherwise NginX will cache the error page as if it is a valid page. Please make sure to unset/remove all headers on your 404/Error pages. Or if not possible, set a no-cache header as explained below, and as explained in this article.

	ExpiresDefault A0
	Header set Cache-Control &quot;no-store, no-cache, must-revalidate, max-age=0&quot;
	Header set Pragma &quot;no-cache&quot;

ExpiresDefault A0

Header set Cache-Control "no-store, no-cache, must-revalidate, max-age=0"

Header set Pragma "no-cache"