I love the way this guy states the incredibly obvious and then leaves the real meat and potatoes up to you and your ESP to determine: ... Tips for Ramping Up With a New ESP and IP Address Starting out with a new email service provider (ESP) will likely mean some growing pains as you make the transition. To prepare you for the move, be prepared for the switch to a new IP address too. As with the switch to the new ESP, the new IP address will require some ramping up as well. Remember that this isnâ€™t an overnight event. Unfortunately, you donâ€™t get to flip a switch and have all the ISPs welcome you with open arms. As with getting to know a new person, getting to know your new IP addressâ€”and reputationâ€”takes time. Know that ramping up with a new IP address can take anywhere from a few weeks to over a month depending on the size of your list. Your sending reputation is IP address based. When you change to a new IP address as you inevitably will when you switch to a new ESP, you must go through this process. The ISPs will simply view you as a new kid on the block at first, and theyâ€™ll be suspicious of huge, bulk mailings coming from this new IP address. Thatâ€™s because spammers will buy a new IP address and blast the heck off of it until they are blocked. By being new and suddenly emailing in bulk, youâ€™ll look like a spammer. However, if you follow these email marketing best practices, youâ€™ll establish a clean reputation from the start. As you make the transition, you must send out smaller numbers of emails, meaning youâ€™ll probably only be able to email a portion of your list at a time. It may seem extremely tedious to conduct sends every day and limiting to only send to a portion of your list, but if you want to properly season your IP address and have the most optimal reputationâ€”and therefore email deliverabilityâ€”at the end of the process, give yourself enough time to complete the process thoroughly to eliminate possible issues in the future. Also, during this ramp up time as youâ€™re parceling out your emails in limited quantities, be particularly vigilant of bounces and complaints. Consider it a short-term investment for long-term gain. Your ramp up time might take longer that a few weeks if your email isnâ€™t perceived as opt-in by the ISPs, so always be practicing email marketing best practices, especially when it comes to signups. Consider revisiting email marketing best practices you might want to hone up on ahead of time. Gmail, Yahoo, AOL, and Hotmail are the most important ISPs. Each will react differently to your new IP address, and each must be warmed up separately. Your new ESP (or ClickMail if weâ€™re your ESP source) will suggest a ramp up schedule for you that takes into account the rate at which you can build up your quantities per ISP. Follow it. ... Source: http://clickmailmarketing.com/whitelist/ Doh! My condensed version for a suggested re-write: Tips for Ramping Up With a New ESP and IP Address Ask your ESP please.