Posting forms to a custom 404 Classic ASP URL in IIS7: where is the post data?

Question

Have recently migrated a number of websites from an ageing Windows 2003 server running IIS6 to a new Windows 2008 server running IIS7.

The sites all use a CMS written in classic ASP which requires that the 404 error is modified to load a default.asp file which looks at the URL and loads content from a database. This is just to keep all the URLs nice and SEO friendly.

The back office of the CMS works in a similar way (except the 404 error is dealt with by admin/default.asp).

For some reason though, the login page (which obviously involves a form posting to the custom 404 error) does not carry over the POST information.

OK - here's the weird bit. It works fine in Google Chrome, but not in IE7/8 or Firefox.

Obviously this is right royal pain in the harris.

Any ideas why post data is carried through the custom 404 handler for one browser but not any others?

I've got as far as I can and am currently trawling the web for information about this but can't seem to find anything...

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OK - here's an update for the weird bit.

It works fine in Safari as well as Google Chrome - but not in IE7/8 or Firefox.

???

Answer 1

I'm not sure this helps, but check this question Posting forms to a 404 + HttpHandler in IIS7: why has all POST data gone missing? and this hotfix by Microsoft