IP warming

New sending IPsStands for "Internet Protocol". The IP address is assigned to one or more devices that are connected to a network. The IP address serves as a unique identifier of the device. have no sending history and are considered a cold IP. At this point they need to acquire a good reputation with ISPsStands for "internet service provider".

Hotmail, Yahoo!, AOL, Gmail will need to see that you are sending important, consent-based messages to permit your mailings into your recipient's inbox.

IP warming is the process used to build a good reputation with ISPs. ISPs will monitor your IP to track your sending behaviour and are likely to accept your messages based on a good sending reputation.

The IP warming process includes sending consistent, low volume email campaigns, gradually increasing this volume over time until you have reached your full volume capacity. ISPs will then gain confidence in you as a sender.

It can take 4-6 weeks to complete the IP warming phase. This depends on your volume amount and how well your recipients are engaging with your messaging.

During the warming process, ISPs will set receiving limits on your IP until you have met their standards of good reputation.

Getting started with IP warming

• Whitelist the Episerver sending IP with your internal corporate network to ensure emails are not blocked by your internal spam filter.
• Ensure your IT team updates your DNS authentication records.
• Clean your data using segmentationThe generic term for dividing recipients into relevant groups, in order to send them appropriate content. Episerver Campaign uses Target Groups and Click Profiles for segmentation. and email validation tools. Warm your most active users only during IP warming phase. Active emails addresses consist of those who have recently opened, clicked an email in the last 9 months or email addresses that have opted-in to your mailings using a double opt-inA practice in which a recipient consents to receiving email from the sender before any promotional email is sent. Recipients receive an email with a double opt-in link, which they must click to confirm their interest. database. Focus primarily on recipients who are less likely to report spam complaints. Never send to a bought or an old unverified email list.
• If you don’t have engagement data to identify active email address focus on your recent signup data.
• Create email content that encourages recipient engagement and that is specific to the recipient's interests. See also: Email content best practices.
• Send a welcome email to your recipients. This acts as a reminder to your recipients that they have opted-in and generates engagement for your first send out.
• It is normal to see some blocking and bulking in the first instance of sending, as a new sender. ISPs are trying to determine your legitimacy, as you continue to send to good active email addresses and increase user engagement, bulking should end.
• Review your engagement data (opens, clicks), a decrease in engagement can lead to your messages being bulked by the ISP. Remove recipients from your marketing campaigns who are consistently not engaging.
• Frequency is important, ISPs like to see consistency in your sending and user engagement metrics.
• Reputation systems store reputation history for 30 days. Ensure that you do not go without 30 days of sending from an IP. Do so may require you needing to restart the warming process.

IP warming schedule

Following an IP warming schedule assists in gradually establishing a reputation with ISPs as a legitimate email sender. Start with small volumes, and gradually increase the volume of email each day or week according to the two-week set schedule. The following schedule suggests a maximum of 40 percent to 100 percentage increase in volume per day. This however will greatly depend on several factors including list hygiene, how engaged your recipients are and spam complaints among other things.

Day	Daily sending volume
1	500
2	1000
3	2500
4	5000
5	10000
6	20000
7	40000
8	60000
9	100000
10	150000
11	200000
12	250000
13	300000
14	400000
	Continue to double your volume until you have reached your target daily volume.

Tips during the IP warming process

• Ramp up your volume "by domain" if you have domains such as Hotmail, Gmail, Yahoo that make up at least 10% of your list. A domain-specific plan may be required, please request and follow a tailored warming schedule provided by Episerver customer support.
• Limit AOL sends to 1,200 daily until your IP is eligible for higher limits.
• Ensure that you are sending consistently and keep to that frequency.
• ISPsStands for "internet service provider" like AOL want to see spam complaints less than 0.2%. Review email engagement on each send, remove recipients who are not opening.
• Once your IPStands for "Internet Protocol". The IP address is assigned to one or more devices that are connected to a network. The IP address serves as a unique identifier of the device. exceeds the threshold set by the ISPs, the ISP may start to soft bounceSoft bounces occur when emails cannot be delivered due to temporary problems. This can happen, for example, if a recipient's mailbox is full. Mailboxes that reject mailings via soft bounce may be available again at a later date. the emails. If you experience a higher than normal soft bounce rate, stop sending and re-start the send later in the day.
• Start the day with recipients who are very likely to open your emails.

What can cause delivery issues during IP warming

• High spam complaints, this occurs when a recipient clicks "this is spam" button which is shown within the email client.
• Invalid email addresses (hard bounceHard bounces occur when an email cannot be delivered due to a permanent error (for example because the email address no longer exists).).
• IP address and domain blacklistings on RBLs (public blacklistsRecipients whose email addresses are on the blacklist will never again receive email from you. This applies even if recipients subscribe to newsletters again later. To reverse this status, remove the recipient from the blacklist.).
• Spam traps located within your data list.
• Unexpected volume increases.

What ISPs like to see

• Consistent opens and clicks
• Consistent email frequency
• Email best practices are put in place, as detailed in Deliverability best practices
• Emails are authenticated (SPF, DKIM, DMARC)

Warming a sending domain

A sending domain requires a good sending reputation for messages to enter your recipients’ inboxes. Domain warming is similar to IP warming as it represents mailing practices and volume. The same warming approach as mentioned before can also be applied for warming up sender domains. The difference however is that domain warming focuses on recipient engagement which is the key factor that you should focus on.