Re: Expires: header not working?

Karl writes:

>Hello,
>
>I've come across a problem with the 'Expires:' header not working
>properly... I've tried installing a web-based email reader called MailMan,
>the problem is that users connecting to the mail machine through our squid
>proxies can read each other's email, because Squid (2.0PATCH1) is cacheing
>the pages.. here is the header info that the web server gives:
>
>office:/var/lib/httpd/htdocs/mail$ telnet localhost 80
>Trying 127.0.0.1...
>Connected to localhost.
>Escape character is '^]'.
>GET /mail/ HTTP/1.0
>
>HTTP/1.1 200 OK
>Date: Wed, 02 Dec 1998 20:24:09 GMT
>Server: Apache/1.3.1 (Unix)
>Set-cookie: MailManAuth=;path=/mail/; expires=Sun, 03-May-1998 16:00:00 GMT
>Set-cookie: MailManCmds=;path=/mail/; expires=Sun, 03-May-1998 16:00:00 GMT
>Expires: Sun, 03-May-1998 16:00:00 GMT
>Connection: close
>Content-Type: text/html
>
>This tells me that the page expires before it's served, no? However the
>page still gets cached by Squid... I've tried changing the Expires: header
>to 'Now' (instead of the fixed date) to no avail..
>
>Can anyone help me fix this? The only solution I've found is to turn off
>caching for the entire site by using no_cache, but there is a lot of
>other information on this server that I want to cache...

Expires does not equal cachability. Expired pages can be cached.

If you have control over MailMan, then have it insert

        cache-control: no-cache

as one of the headers.

Presumably, when a second user requests this cached page, Squid should
issue an IMS request. MailMan should not return a 304 reply for the
IMS request.

Duane W.
Received on Wed Dec 02 1998 - 18:10:22 MST