Apple iCloud Mail — Postmaster Requirements

Apple publishes a single postmaster document (support article 102322, last published 2025-02-25) covering the domains mac.com, me.com, and icloud.com. 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.

Requirements for sending bulk email

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

#	Requirement
1	Send only to recipients who explicitly subscribed — no list purchases, list rentals, or email appends
2	Offer an unsubscribe link so the recipient can unsubscribe immediately
3	Add ARC headers to forwarded emails
4	Comply with RFC 5321 and RFC 5322
5	Publish reverse DNS (PTR) with your domain to help identify your IPs
6	Use consistent sending IPs and domains, but segment marketing and transactional streams
7	Use a consistent From: name and address that clearly identifies your brand
8	Authenticate with SPF and DKIM
9	The sending domain must publish a DMARC policy
10	Track temporary and permanent SMTP errors from Apple's servers and act on them
11	Have a standard bounce-handling policy
12	Periodically remove inactive subscribers
13	Never reactivate addresses already on your unsubscribe/suppression list

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

Notable relative to other providers: the explicit ARC-on-forwarding requirement and the mandate to segment marketing from transactional on separate streams — see Advanced IP Segmentation.

How iCloud Mail filters

• No allow list. Apple explicitly does not offer one. Filtering decisions come from sender reputation tracked via IP reputation, domain reputation, content checks, and user feedback.
• No feedback loop (FBL). Apple does not offer one. Because you get no complaint signal back, list hygiene is your only proxy — 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; even legitimate mail can occasionally be misfiled as junk.

The absence of an FBL and allow list makes engagement-based hygiene the whole game 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 sending domain's DMARC policy 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 claiming to be from an iCloud address that fails SPF and DKIM should go to Junk.
• To learn Apple's outbound IP ranges, query the SPF records of mac.com / me.com / icloud.com — that is the published source of truth for their outbound IPs.

Practical consequence: never spoof an @icloud.com / @me.com / @mac.com address in your From:; receivers enforcing Apple's quarantine policy will junk it. See DMARC.

Diagnosing rejections and the unblock process

There is no self-service unblock form. The process is:

1. Read the SMTP error. Apple's mail servers return SMTP errors explaining why a connection or message was rejected; most include a URL with more information. Check your mail logs.
2. Fix against the requirements table above (Apple's stated first remedy is "follow the best practices").
3. Escalate to the postmaster team only if steps 1–2 don't resolve it, by emailing 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

Non-administrators (end users) should contact Apple Support instead — icloudadmin@ is for system administrators only.