We are running MIIS 2003 with 5 Exchange Sites in multiple environment. Main domain is @XYZ.COM, Sites are with forest ABC1.NET, XYZ1.NET, QRST1.NET etc.
There is strange change, there are TWO PRIMARY SMTP ADDRESSES in Default Policy of Exchange 2003. When we delete or disable/uncheck one, it says, "The SMTP Primary address cannot be disabled all recipients must have an smtp address in Miscrosoft Exchange".
If we create new SMTP address and make it primary, one of TWO Primary Addresses changes to secondary other remain primary, its mean still TWO PRIMARY ADDRESSES.