A few months ago email being sent from my company were being rejected by some spam filters. After looking into it I found that exchange 2007 places the internal IP address in the header, which is a private address. Exchange 2007 does this by default. Each time an SMTP email is passed from one server to another, the receiving server records the hand-off in the SMTP headers of the email. This is usually recorded like this: Customers often do not like their internal email infrastructure exposed in the...