OWA 2000 uses the WEBDAV extensions to the HTTP protocol. Raptor's HTTP proxy (httpd) doesn't recognize all WEBDAV commands and consequently denies access when it encounters unimplemented commands for security reasons. The first thing I would try is to update Exchange to service pack 2.
If that does not work try this..
The best method for circumventing this issue is to pass OWA traffic over a secure session (SSL) using HTTPs instead of clear-text HTTP. This has two benefits:
1. The Raptor Firewall HTTP proxy cannot examine the encrypted session data and therefore lets any HTTP commands pass. It still provides security inasmuch as the assumption is if the two servers trust each other enough to setup an SSL session, then they must also trust each other to behave properly within that session.
2. Encrypting your corporate e-mail, calendar, and contacts across the open Internet is a recommended security practice; passing potentially sensitive information in clear-text is just a plain bad idea.
Configuring ISS for HTTPs is fairly trivial: It requires the acquisition and installation of a server certificate. We recommend using a certificate from a valid root CA, such as VeriSign or Entrust, not a test certificate which hasn't been signed by a valid CA. If you run your own CA, you should already know how to generate a signed certificate and distribute the CA certificate to your end-users.
Hope this helps,
Nick
