[Mod_gzip] "mod_gzip_send_vary=Yes" disables caching on IE? (1.3.26.1a)

[Jordan Russell]

TOKILEY@aol.com wrote:
> What is the actual point of this thread?

That IE treats "Vary: Accept-Encoding" on (only) uncompressed responses as
apparently meaning "don't cache". This wasn't an issue with older versions
of mod_gzip because they did not send this header.

> (Jordan?) says
> that MSIE isn't caching ANY of the non-compressed variants
> if they have ANY kind of "Vary:" header.

Yes, that is my experience. It always reloads the pages when navigating the
history list (using the Back and Forward buttons), and it always reloads
them when you visit them later -- no If-Modified-Since request header is
sent (if the last visit had a Last-Modified response header), and any
Expires response header from the last visit (that was non-compressed and
contained a Vary header) isn't respected.

> What (Exact) versions and build levels of MSIE are
> we talking about here and does one really actually
> WORK while another does NOT?

With this test:

header("Vary: Accept-Encoding");
header("Expires: Mon, 08 Dec 2003 00:00:00 GMT");
echo "Hi";

Here are the versions I tested. All of them "did not work" -- they reload
the page every time.

- IE 6.0 + all latest updates:
  6.0.2800.1106 ;SP1;Q328970;Q324929;
- Plain IE 6.0:
  6.0.2600.0000
- IE 5.5 SP2:
  5.50.4807.2300 ;SP2;
- Plain IE 5.0:
  5.00.2920.0000

> Where does Netscape fit into all this?

I haven't personally tested this.

Jordan Russell