Here is the situation.  I have built an web application to manage my client's Email Blasts.  Blast volume could range from 2000 emails up to 80K per blast and they would go out every couple days.  I have my application setup to manage a queue of emails waiting to go out, with a service selecting emails off the top of the queue and passing them on to smartermail for delivery every minute or so.  The idea is to let the emails trickle out slowly.  I know from experience that most of the larger domains (yahoo, gmail, aol) will only accept a limited number of emails per 24 hours before they start throwing them into the spam folder. How many emails they accept is determined by your reputation and daily averages.  What I want to do is send the emails out from multiple outgoing IPs.  I want to create a primary domain instance in smartermail (news.mydomain.com) and then send the email from (alerts@news.mydomain.com), but I am unsure how to tell smartermail to send the emails out on various IPs other than the primary for the domain. I currently have 3 IPs I want to use for this, and I have setup the IPs and hostnames in smartermail.  But of course when smartermail sees an email going out from news.mydomain.com it will force it to go out on the primary IP for that domain.  Any feed back in how to make this work?

 

The only other way I know how to do this is setup each IP as its own domain

news1.mydomain.com

news2.mydomain.com

news3.mydomain.com

 

and then send the emails out as 

alerts@news1.mydomain.com

alerts@news2.mydomain.com

alerts@news3.mydomain.com