If you are sending mail to a list of 15,000 people, you need processes to handle bounces and complaints, remove people who don't want to be on the list any more, and do all the rest of the stuff that's required for legitimate list management. Postfix is a dandy MTA, but it doesn't do that.
Outsource your list to a competent ESP who already knows how to do it correctly. The modest cost is well worth it. For a list of that size, I'd look at Mailchip and Constant Contact. Regards, John Levine, jo...@iecc.com, Primary Perpetrator of "The Internet for Dummies", Please consider the environment before reading this e-mail. http://jl.ly
