Apple iCloud Mail — Postmaster Requirements

If you send bulk email to addresses at mac.com, me.com or icloud.com, your mail must meet every one of Apple's requirements, or it will be rejected. Unlike Gmail or Yahoo, Apple publishes no numeric thresholds, but it states plainly that all requirements must be met or the email will be rejected.

Apple sets out its rules in a single postmaster document, support article 102322, last published on 2025-02-25.

Requirements for sending bulk email

Every item below is required, and failing any of them is grounds for rejection:

Apple also points senders to M3AAWG's best communication practices as a reference standard.

Two requirements stand out compared with other providers: the explicit requirement to add ARC headers when forwarding, and the mandate to separate marketing from transactional mail in different streams (see Advanced IP Segmentation).

How iCloud Mail filters

• No allowlist. Apple explicitly does not offer one. Filtering decisions come from sender reputation, tracked through IP reputation, domain reputation, content checks and user feedback.
• No feedback loop (FBL). Apple does not offer one either. Because you get no complaint signal back, list hygiene is the only substitute. Apple's own advice:
  • periodically suppress inactive or disengaged subscribers;
  • remove addresses that bounce consistently;
  • honor unsubscribe requests as soon as possible.
• Junk mail is detected and blocked before it reaches the inbox, and even legitimate mail can occasionally be misfiled as junk.

With no FBL and no allowlist, hygiene based on engagement is all you can rely on at iCloud. The "wanted and expected" principle in Foundations applies with no safety net.

Apple's own authentication posture (inbound and outbound)

• iCloud Mail authenticates all inbound mail with SPF and DKIM.
• iCloud Mail honors the DMARC policy of the sending domain on inbound mail.
• All iCloud domains publish SPF records and sign all outbound mail with DKIM.
• All iCloud domains publish a DMARC policy of p=quarantine (in effect since July 2, 2018). Mail that claims to come from an iCloud address but fails SPF and DKIM should go to Junk.
• To find Apple's outbound IP ranges, query the SPF records of mac.com, me.com and icloud.com. They are the published source of truth for Apple's outbound IP addresses.

In practice, never put a spoofed @icloud.com, @me.com or @mac.com address in your From: header. Receivers that enforce Apple's quarantine policy will send it to Junk. See DMARC.

Diagnosing rejections and the unblock process

There is no self-service form to request unblocking. The process is:

1. Read the SMTP error. Apple's mail servers return SMTP errors that explain why a connection or message was rejected, and most include a URL with more information. Check your mail logs.
2. Fix the problem using the requirements table above. Apple's first recommended remedy is to "follow the best practices".
3. Escalate to the postmaster team only if steps 1–2 do not resolve the problem. Email icloudadmin@apple.com with all of the following:
   • your company name
   • your email domain
   • the IP addresses of the affected mail servers
   • the SMTP errors received from iCloud mail servers
   • a detailed description of the issue, including when it started

People who are not administrators (end users) should contact Apple Support instead, because icloudadmin@ is only for system administrators.