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I have a Windows 2008 server that has three IP bound to the NIC. I can select which IP Windows SMTP listens to, but I want to also set the IP address used when mail is sent. Where would I set which outbound IP to use when sending email?

Without using real IPs, here is an example what I have setup. Three IPs associated with the server:

I setup the binding on for port 25 in the SMTP server settings, so that it is the only IP that will respond for inbound. When I look at the email header from an email sent from that server, it lists the server with an address of I would like it to use so that when reverse DNS is performed, it maps back correctly.

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Maybe I need to look at Windows routing tables: - Myth #4 – Josh Mar 18 '10 at 15:57
Hey! Nice username you've got there ;-) – Josh Mar 18 '10 at 18:53

A specific smtp server instance only binds to one address. If you want to separate them then you need to fire up a second server, but it'll have to bind to a different port (which shouldn't be that big of a problem for outgoing traffic).

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I tried creating a separate instance, I used a different IP for it to listen and I assigned a different port to the original instance. But the new one used the same IP for sending emails as the first instance. – Josh Mar 18 '10 at 15:38
Which version of Exchange are you using? – Mufasa Mar 19 '10 at 22:41
I'm not, this I'm using the SMTP Server that comes with Windows Server – Josh Mar 22 '10 at 17:49

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