ASP.NET Redirect behind proxy fails, ASP 3.0 works

[Andy Todd]

Hi

We have just moved an ASP.NET application into the live environment which is
as follows:

Sun Proxy Server / Firewall
Windows 2000 Server / IIS5

The URL for the site maps to the Sun proxy box. This translates the request
and maps it to the Win2K server which responds through the proxy. The Win2K
box has no direct connection to the internet. AFAIK the Win2K box knows
nothing about the "real" URL being requested.

We have a problem when issuing a Response.Redirect for a relative path from
ASP.NET. The code looks like:

Response.Redirect("home.aspx",false);

The redirect sends the URL from the Win2K box back to the client with a 302
status - the client then requests home.aspx, but incorrectly using the URL of
the Win2K server.

For example:

- HTTP Post: http://dev.dfes.gov.uk/progressfile/wideninghorizons/index.aspx
- index.aspx issues a redirect to home.aspx
- Browser recieves this as 302 and is given the URL
http://dev.dfes.gov.uk/0215wideninghorizons/home.aspx
- Request fails the URL SHOULD be
http://dev.dfes.gov.uk/progressfile/wideninghorizons/home.aspx

/0215wideninghorizons/ is the Virtual directory on the Win2K box.

We could code around this, but as a test I wrote an ASP 3.0 page and an
ASP.NET page which both issue just one command;
Response.Redirect("home.aspx");

When I run both of these the ASP 3 page succeeds and redirects to the
correct URL. The ASP.NET page however fails. Also a test with
FormsAuthentication.RedirectFromLoginPage() fails, sending the user to the
wrong URL.

We could code around this, but it looks like either a bug in Redirecting in
ASP.NET, or there's something I don't know about the config which could help.

Any suggestions greatly appreciated.

Thanks
Andy