Hey We are using Exchange 2003 SP2. If I check my AD properties > Email Addresses, then I can see the following: smtp: sheen@email.company.com smtp: sheen@email.oldcompany.com SMTP: sheen@company.com I know SMTP is the Primary SMTP addresss, which I gather means that any replies/new emails will be sent using that address. But Exchange will also accept email for my mailbox on the 'smtp' addresses? But how can I find out which address(es) Exchange is primarily responsible for/authorative for? We have a 3rd Party gateway solution as well where our MX for company.com points to, so I'm not sure which address Exchange actually uses to route email internally? For example, if I added kam@microsoft.com to that list of my addresses in AD, I know that I can still recv internal mail on that address. Does anyone know how I can find out which address Exchange actually uses (I think it maybe the LegacyExchangeDN but I'm not 100% sure) to route messages?

You are correct that the additional proxy addresses are all valid addresses for that particular mailbox. Once a message is accepted by Exchange, it no longer uses the SMTP address to route messages internally. This might have changed with E2K7 or E2K10 (though I know it is still used), but the LegacyExchangeDN continues to be used to uniquely identify the mailbox. That is not used to directly deliver e-mail, per se, but Exchange uses that information to then determine on which mailbox server the mailbox is located and then routes the message based on the location of the mailbox server (via bridgeheads) Jim McBee - Blog - http://mostlyexchange.blogspot.com

On Sun, 25 Jul 2010 12:56:24 +0000, Sheen1990 wrote: >Hey We are using Exchange 2003 SP2. If I check my AD properties > Email Addresses, then I can see the following: smtp: sheen@email.company.com smtp: sheen@email.oldcompany.com SMTP: sheen@company.com I know SMTP is the Primary SMTP addresss, which I gather means that any replies/new emails will be sent using that address. But Exchange will also accept email for my mailbox on the 'smtp' addresses? That's correct. >But how can I find out which address(es) Exchange is primarily responsible for/authorative for? All of them. >We have a 3rd Party gateway solution as well where our MX for company.com points to, so I'm not sure which address Exchange actually uses to route email internally? For example, if I added kam@microsoft.com to that list of my addresses in AD, I know that I can still recv internal mail on that address. Does anyone know how I can find out which address Exchange actually uses (I think it maybe the LegacyExchangeDN but I'm not 100% sure) to route messages? You gateway should be using LDAP to query the Active directory for valid SMTP addresses. If it can't, then you should be periodically exporting the set of valid SMTP addresses from the AD to the gateway. --- Rich Matheisen MCSE+I, Exchange MVP --- Rich Matheisen MCSE+I, Exchange MVP

Hi Sheen1990, 1. All of address could be accept by Exchange from outside. 2. All of these email address are authoritative. 3. “LegacyExchangeDN” is the property to identify the location of mailbox, internal client, for instance, outlook use “LegacyExchangeDN” to locate user’s mailbox.