How to Allowlist Delivery IP Addresses

If your contacts at a certain company or private email domain have trouble receiving Mailchimp emails, you may want to ask them to allowlist Mailchimp’s delivery IP addresses as a possible solution.

Private email domains tend to have more aggressive firewalls and spam filters than Gmail or other free webmail providers. Sometimes, these network firewalls and filters can block your campaigns.

In this article, you'll learn about allowlisting, and when and how to request it.

Things to know

• This article details allowlisting with delivery IP addresses, but you can also allowlist domain addresses or specific emails by adding them to a Safe Sender’s list in an email client.
• Delivery IP addresses sometimes change. When we update IPs, we'll publish updates on our IP Address page.
• URLs added as text links, button links, or clickable image links in your email can also cause your email to be blocked by a security program. If you've already had a contact allowlist Mailchimp IPs and are still being blocked, it's a good next step to check your own content for something that triggered the email to be blocked.

About allowlisting

Allowlisting (other providers may refer to it as "whitelisting") IPs is a process that grants permission to deliver emails to a specific email address, domain, or network by creating a list of trusted IP addresses or domains. The process varies by organization and email clients. For example, if your company has a private email server, they can allowlist delivery IP addresses through an email client, or allowlist traffic through a domain firewall.

This is the opposite of denylisting (other providers may refer to it as "blacklisting"), which is intended to identify and block harmful senders. A denylisted email may always end up in the junk folder, or never make it to an inbox at all.

For more guidelines on how to make sure emails end up in the right inbox, check out our articles on email deliverability and spam filters.

When to allowlist

Before you ask contacts to allowlist Mailchimp IPs, review these questions to see if private domain settings might be responsible for delivery issues.

• Do all people with addresses at a certain private email domain, like @pottedplanter.com or @example.org, have trouble receiving campaigns or messages from your Mailchimp account?
• Did affected contacts check their spam or junk folders and still not see your campaign or message?
• Have affected contacts at the domain allowed enough time for campaigns or messages to arrive?

If you answered yes to these questions, allowlisting might help deliverability at the affected domain.

Allowlist by delivery IP

To improve delivery with allowlisting, an IT professional at the affected domain will need to change the configuration of the receiving email server to accept mail from Mailchimp's delivery IP addresses.

To start the process, follow these steps.

1. Reach out to the affected contact and explain that a network firewall or spam filter at their domain could be blocking Mailchimp campaigns.
2. Ask the contact to copy this link and forward it to their IT department.
   https://www.mailchimp.com/about/ips/
3. The IT professional should then follow the instructions on the Mailchimp IP site to calculate the complete range of our IP addresses. After they have the full IP list, they'll need to allowlist all Mailchimp IP addresses on their domain.

Next steps

For more information about how to set up your emails for delivery, and how we educate our users about proper audience management and etiquette, visit these links.

• Verify an Email Domain
• About Email Authentication
• Mailchimp Abuse Desk