Postmaster information for iCloud Mail

If you are a system administrator who manages mail servers that send email to iCloud Mail, learn about sending bulk email, email authentication, delivery issues, and more.

What are the best practices for sending bulk email?

You should use these best practices when you send bulk mail to iCloud Mail customers:

  • Send only to recipients who explicitly subscribed to your emails (not list purchases, list rentals, or email appends).

  • Offer an unsubscribe link, so that the recipient can unsubscribe immediately.

  • Ensure emails are compliant with RFC 5322.

  • Publish reverse DNS with your domain to help identify your IP addresses.

  • Use consistent sending IP addresses and domains for your bulk email, but do segment marketing and transactional email streams.

  • Use a consistent From: name and address to clearly identify your brand.

  • Make use of Sender Policy Framework (SPF) and DomainKeys Identified Mail (DKIM) to authenticate your emails.

  • Track the temporary and permanent SMTP errors from our mail servers and act on them accordingly.

  • Have a standard policy for handling bouncing addresses.

  • Periodically remove inactive subscribers from your list.

  • Don't reactivate email addresses that are already on your unsubscribe or suppression list.

You can also go to the Messaging, Malware and Mobile Anti-Abuse Working Group (M3AAWG) website and check their best communication practices.

Does iCloud Mail offer an allow list for bulk senders?

We don't. We track a sender’s reputation using various mechanisms, such as IP and domain reputations, content checks, and user feedback. Then we make our filtering decisions.

Does iCloud Mail offer a feedback loop service?

We don't offer a feedback loop (FBL). We do encourage bulk email senders to manage the subscribers list, so that only engaged subscribers keep receiving your emails. Here are a few ways to maintain your subscribers list:

  • Periodically suppress inactive or disengaged subscribers from your mailing list.

  • Remove addresses that bounce consistently.

  • Honor unsubscribe requests as soon as possible.

Email authentication

Learn more about email authentication in iCloud Mail.

What are the IP addresses that send for iCloud Mail?

All iCloud Mail domains (,, and have a published SPF record. Check our SPF record to see the current IP ranges we use for outbound mail.

Does iCloud Mail use email authentication?

iCloud Mail authenticates all inbound emails using SPF and DKIM. We also publish SPF records for our domains and sign all of our outbound emails with DKIM.

Does iCloud Mail support DMARC?

If a sending domain publishes a Domain-based Message Authentication, Reporting, and Conformance (DMARC) policy, iCloud Mail honors the domain's policy. All iCloud Mail domains also have a DMARC ("p=quarantine") policy*, which indicates to a mail provider that an email from an iCloud email address that fails SPF and DKIM email authentication should go to the recipient's Junk folder.

*The policy took effect on July 2, 2018.

Delivery issues

Use the recommendations below to make sure that your recipients get your email.

Why don't our messages go to the recipient's inbox?

Please follow the best practices for sending bulk email, so that your emails won't be considered junk mail. iCloud Mail automatically detects and blocks junk mail before it reaches the inbox. We do our best to ensure that all legitimate and wanted emails get to our users, but occasionally those emails might be filtered as junk.

How can I resolve delivery issues to iCloud Mail?

When refusing SMTP transactions, our mail servers generate SMTP errors with information about why your connection or message was rejected. To find the error message, check your mail logs. Most of the errors will also include a URL that provides more information.

If you still need help

If you followed our best practices and reviewed your mail logs for more information but still can't diagnose and address delivery issues, you may contact our postmaster team by sending an email to with all of the following information:

  • Your company name

  • Your email domain

  • The IP addresses of the affected mail servers

  • The SMTP errors that you're getting from iCloud mail servers

  • A detailed description of the issue, including when it started

If you're not a system administrator and need help with iCloud Mail, contact Apple Support instead.

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