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

[Jordan Russell]

I wrote:
> After further testing, I've found that IE 6 *will* cache a page containing
> "Vary: Accept-Encoding" just fine *if* there's also a "Content-Encoding:
> gzip" header. It's only the files that mod_gzip sends back uncompressed
with
> no Content-Encoding header that are not being cached.

It's even more strange than I first thought...
Without "Content-Encoding: gzip", it appears IE 6 will not cache pages
containing *any* type of Vary header. (By "will not cache" I mean that after
the page is loaded once, it is reloaded every time you pass by it using
Back/Forward.)

Below are some tests I performed with PHP. mod_gzip was not installed.

This will cache:

  echo "Hi";

This will NOT cache:

  header("Vary: Accept-Encoding");
  echo "Hi";

This will NOT cache:

  header("Vary: blahblah");
  echo "Hi";

This will cache:

  header("Content-Encoding: gzip");
  echo gzencode("Hi2");

This will cache:

  header("Vary: Accept-Encoding");
  header("Content-Encoding: gzip");
  echo gzencode("Hi2");

This will cache:

  header("Vary: blahblah");
  header("Content-Encoding: gzip");
  echo gzencode("Hi2");


Jordan Russell