How to warm up an IP address

Rob Howard Updated by Rob Howard

When you transition from one Email Service Provider to another you will change IP addresses too - or use an IP address that have never been used to send email before.

An IP address is a number that uniquely identifies a computer connected to the Internet.

When email systems, such as Microsoft, Gmail, Aol and others see activity from a new IP address they often delay delivery of those messages until the IP address appears to be trusted. This is because spammers often switch IP addresses and send a high volume of email.

This process, known as warming up an IP address, describes the steps you should take and what you should expect when sending email from a new IP address. This allows your sending reputation to build over time as your customers accept your messages.

Warming up an IP address can take 30-90 days.

Setting Expectations

We'd love to tell you that warming up a new IP address is simple. Unfortunately it's more art than science as each mailbox provider has their own rationale for how they trust a new IP address.

Before sending any email to warm-up and IP address we recommend verifying all of your settings and validating that your message has a low SPAM score.
  • High number of soft-bounces - it is likely that during the warm-up of your IP address you will see a high number of soft-bounces. A soft-bounce if a mailbox provider delaying the delivery of your message because it detects an unusual spike in volume from an an unknown IP address.
  • Decrease in inbox placement - as your IP reputation grows, so will your inbox placement (vs ending up in SPAM folder). Unfortunately this takes time and there is no set guidance. However, you can encourage your customers to white label your domain.
Some mailbox providers will purposefully move email to SPAM to see if readers mark the messages as "not spam". When warming up an IP address try and reach out to some of your best customer first and ask them to look for your emails.
  • Your reputation doesn't transfer - unfortunately your sending reputation does not transfer with your domain, it is attached to the IP address. Mailbox provides like Gmail build reputation on domain plus IP address.

Recommend Best Practices

Below are some recommended best practices for warming up a new IP address.

  • A slow warm-up is best - it is best to proceed slowly with a new email warm up. If you suddenly see a spike in soft-bounces or failed messages, it's probably best to slow down the number of messages you are sending.
  • Your results may vary - different mailbox providers handle the warm up process differently. Some providers, such as Outlook, can take longer than providers such as Gmail.
  • Randomize the warm-up - if possibly try and randomize the warm-up across mailbox domains. For example, don't group all AOL emails to send on the same day. Rather, break them up proportionally in your warm-up schedule.
  • Start with your most engaged recipients - these recipients are ones that routinely interact with your messages, click on your offers, etc. These recipients will help signal to the mailbox provider that your email is legitimate.
  • Distribute sends through-out the day - rather than sending all of your messages at once, try and distribute the sends through out the day. This will help ensure that mailbox providers don't see a sudden influx, but gradually warm-up to your new emails.

An Example Schedule

Putting together a plan for how you warm-up an IP address or set of IP addresses is important. And, you want to make sure you have the time to dedicate to monitoring your email delivery.

For a known email list, such as when transitioning to DailyStory from another Email Service Providers, we recommend starting small. For example, if you routinely send 100,000 emails per month, we would recommend a sending schedule as follows:

  • Days 1 - 10 - send 1 percent day 1 and increment by 1%/day for the next 9 days. If any delivery issues occur step back 2% and build up again.
  • Days 11-15 - increment by 2%/day for the next 5 days. Back off by 2-4% if any delivery issues occur.
  • Days 16-20 - increment by 5%/day for the next 5 days. Back off by 5% if any delivery issues occur.
  • Days 21-60 - slowly build up by 5-10%/day backing off an restarting until you reach 100%.

During IP Address Warm up

During the warm up process monitor DailyStory's delivery reports. You are likely going to see a high number of delayed delivery. This is normal. Also monitor your reputation and that your IP address and/or domain have not been blacklisted.

If, during your warm up, you start seeing a high number of failures or bonces. It is best to step back to the last point in the warm up where you experienced a high delivery rate.

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