RE: Reload new page .

The problem seems to be that MSIE3 does not distinguish between loading and
reloading via a proxy.

When Netscape is told to reload a page, it adds Pragma: no-cache to the
request. When MSIE3 is told to refresh a page, it simply repeats the request
 - which works fine if there isn't a proxy. The proxy then gives it the one
out of cache, because it hasn't been told to flush its own cache. MSIE3's
refresh simply refreshes the browser's cache, not any proxy's.

To see this, try connecting to the echo port (port 7) on a nearby server,
e.g. for me http://jessica:7/ - you'll see the following with MSIE3:

GET / HTTP/1.0
Accept: image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, */*
Accept-Language: en
UA-pixels: 800x600
UA-color: color16
UA-OS: Windows 95
UA-CPU: x86
User-Agent: Mozilla/2.0 (compatible; MSIE 3.0; Windows 95)
Host: jessica:7
Connection: Keep-Alive

(and then you should hit Stop). If you hit Refresh, you will see an
*identical* request.

If you do this with Netscape, you will see

GET / HTTP/1.0
User-Agent: Mozilla/1.22 (Windows; I; 32bit)
Accept: */*
Accept: image/gif
Accept: image/x-xbitmap
Accept: image/jpeg

But if you hit Reload, you will see

GET / HTTP/1.0
User-Agent: Mozilla/1.22 (Windows; I; 32bit)
Pragma: no-cache
Accept: */*
Accept: image/gif
Accept: image/x-xbitmap
Accept: image/jpeg

and the proxy knows to flush its own cache and fetch you a brand new copy.

I don't think there's any way round this. It may be why the Microsoft home
page is set to be uncacheable (it has an Expires: header for one second in
the past). I handle it by setting a short TTL for Intranet pages to force
frequent reloads.

Ian Redfern (redferni@logica.com).
Received on Tue Sep 24 1996 - 11:31:32 MDT