I was recently alerted to the fact that someone outside of my company has received a message (which was originally denied as spam) and after looking at the header information, it appears that our exchange server is giving away too much information, and also signing headers improperly. 1: When delivering email, our server is claiming to come from our internal subnet, and not using it's external IP address. Is there a configuration setting where I can change how our server identifies itself to the outside world? Our server resides behind a basic firewall, and is only assigned an internal IP address. The firewall then has some basic NAT setup for forward all traffic from an external address to our email server. 2:Our server is apparently not including any X-Mailer tag in our out going email.It is possible this is an isolated incident, as theoffending piece of email was apparently from a windows mobile device, through our server, to therecipient (out of company).So... A: Are there any utilities that I can investigate this stuff myself? I am a bit of an email novice and am not familiar with the utilities that could help look at all this information. B: If this is the case, what would cause our server to send out email without an X-Mailer tag, and how can I fix it? I suspect this may be linked to the mobile device being used, but if anyone has any information on why this would be happening, I am all ears. Some additional notes about the environment. Single server environment, all mail functions are housed on this single server. Windows Server 2003 R2. Exchange Server 2003 Standard. OWA is functional (secure) and RPC over HTTP is enabled(RPC / HTTP is the primary connection method). Activesync is also enabled, but not widely used. Any information is appreciated! Eric Schmidt (Sadly, not the owner of Google)

Exchange always stamp its own IP in the header, how could it know that your Firewall is doing NAT. The name that Exchange advertise itself with can be changed but it will break authentication between other Exchange servers, but since you're in a single server environment this is possible. Be aware though when you add another Exchange server in the future they cannot authenticate SMTP sessions betweeen each others and this will cause some problems.