reverse proxy and file download problems for the client

[Duane Winner <duane@xxxxxxxxxxxxxxx>]

We are running apache as a reverse proxy front-end in our DMZ to forward requests to apache servers in our back-end network segment.

Previously, until a few months ago, we ran one apache instance for each client in the DMZ without reverse proxy, so the apache was both the front-end and the app server (cgi-bin).

One of our clients claims that ever since we moved to reverse proxy structure ago, they are having trouble opening files in Internet Explorer -- it sounds like PDF's only. They say they can "Save to disk", then open, but can't click on URLS and open.

They say they don't have issues with Word documents.

We asked them to try different browsers and pdf readers, and they report back that it works ok with Firefox and FoxIt Reader w/ Internet Explorer.

Because they keep claiming it started when we moved to a reverse proxy structure, we decided to at least test this and set up a test replica of their web app using the old architecture, all in the DMZ
They say IE->Acrobat file opens ok on this test bed.

So it seems there might be something going on w/ reverse proxy, but I'm clueless as to what.

The fact that they can open with Firefox and IE->Foxt Reader still leaves me skeptical that it's our issue, but I can't deny that they proved it works ok when not doing reverse-proxy.

The mime types in httpd.conf are configured the same in both instances, and that's the only configuration area I can think of to play around with, but since they're identical, I don't see what I can try.

Suggestions, ideas?