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Re: How long does an IP address change take?

On Thu, Nov 01, 2001 at 02:53:43PM -0600, Jay Link wrote:
> > After reading Jay's post, I wondered, how is that possible? 1) Jay, how
> > did you learn that?  2) I am sure you mean IP info, and not actual
> > content (IOW, foxnews.com, etc., etc. showing yesterday's news).
> 
> No, I *do* mean actual content, except that you raise a good point:
> dynamic information does seem to be current. So, AOL's "barrier" of
> caching (incoming) web servers must be smart enough to only cache static
> content.
[...]

Most proxy servers are.  Search around for "pragma nocache" and the like.

<HEAD>
	<META HTTP-EQUIV="Pragma" CONTENT="no-cache">
</HEAD>

Will keep most proxies from caching your web page.  HTTP 1.1 supporting
proxise will respect the
	<META HTTP-EQUIV="Cache-Control" CONTENT="no-cache">
tag, and pretty much all of them will respect the
	<META HTTP-EQUIV="Expires" CONTENT="Fri, 02 Nov 2001 11:48:55 CST">
kind of syntax.

It's usually best to use the "expires", as that allows caching proxies to
do their job.  However, if your content is truly dynamic, no-cache will
work fine too.

BTW, CGI authors take note that these are the equivilent of headers
	"Cache-Control: no-cache\n"
and the like.  Finally, note that some versions of IE wills till cache
the page on disk unless you add a second <HEAD> section after the body in
an html document, and put the 'pragma: no-cache' in that second head.  IE
is stupid.

--Danny
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