Warming up a new IP address is a gradual process that happens over time with an end goal of establishing a positive reputation with Internet Service Providers. ISPs are suspicious of sudden spikes in email traffic, especially when it comes from an IP address with no sending history. They will take notice immediately and begin evaluating the traffic coming from that IP which can determine how current and future emails are handled. This is why it’s important to start with your best addresses and gradually ramp up your sending volume.
Listed below are the steps which should be taken when warming up a new IP address:
- Make sure your email list is clean and healthy. This means do not send to any purchased lists or email addresses that have not fully opted-in to receive your mailings. It also means no addresses which have not been sent to recently. When starting out, send only to those which have been successfully sent to within the last 30-60 days.
- Start out by sending to smaller groups. If you have a list of 50,000 addresses you want to send to, break it down into groups of 5,000 - 10,000 and separate them throughout the week. This will help prevent exceeding limitations receiving domains may have on the number of emails they allow from new IP addresses.
- Gradually increase sending volume over 60-90 days. Depending on the quality of the list and how the campaigns are received, the speed at which you can increase may vary.
- Email your most engaged recipients first. Send to those addresses which have recently opened or clicked your campaigns. How recipients interact with email you send is a vital part of how receiving systems judge the IP.
- During your initial sends, extract your permanent failures from reporting after your campaign has completed and re-import them to the database in “held” status. This prevents future campaigns from being sent to and rejected by those recipients which can hurt your deliverability. List hygiene is very important when starting out and you want to be able to prevent the bad addresses from being sent more than one mailing.
- Keep an eye on your reporting. If you notice campaigns are being rejected by receiving servers, you may need to consider reducing your volume. If deliverability is good, you may want to consider slowly ramping up your sends.