Volume 28 Issue 16

Issue Date: July 20, 2023 « Previous Issue | Next Issue »

The following articles were included in our Exchange Messaging Outlook (EMO) newsletter published on July 20, 2023.

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Today's Highlights »

Microsoft 365: New DMARC Policy
Custom domains: SPF and DMARC
Workaround for Mac and Yahoo Syncing
Type / to insert files and more
Missing Calendar in iCloud Add-in

Microsoft 365: New DMARC Policy

Microsoft is updating their DMARC policies for both Outlook.com and Microsoft 365 business accounts.

For Outlook.com users, including Hotmail, Live, and MSN addresses, the DMARC policy now honors the sender’s DMARC policy. If an email fails DMARC validation and the sender’s policy is set to p=reject or p=quarantine, the message will be rejected.

Business tenants using Microsoft MX records can choose how to handle emails that fail DMARC validation and choose different actions based on the policy set by the domain owner. The sender's DMARC policy will be honored, meaning if they use p=reject or p=quarantine, the message will be rejected, as it is in the consumer space. Administrators will be able specify different actions in the Anti-Phishing policy section of the Microsoft 365 Defender portal. If an organization uses a 3rd party server to filter their mail before sending it to Microsoft 365, the policy will not apply. (DMARC policies should be applied on the 3rd party server.)

Messages that fail DMARC validation when the policy is set to reject, will bounce back to the sender with a non-delivery report (NDR) stating it did not pass DMARC:
550 5.7.509: Access denied, sending domain domain.com does not pass DMARC verification and has a DMARC policy of reject

This is rolling out now, with the change taking effect in mid-August. If administrators want to modify the policy, they should do so before mid-August.

Microsoft's announcement:
Announcing New DMARC Policy Handling Defaults for Enhanced Email Security - Microsoft Community Hub

For more information on DMARC and SPF, see
Use DMARC to validate email, setup steps | Microsoft Learn

Custom domains: SPF and DMARC

Anyone using a custom domain for email should have and SPF and DMARC records in DNS. These records tell the recipient server what servers are allowed to send mail from the domain. If a spammer tries to send spam from his server using an address in your domain the SPF record will let the recipient server know if that server is allowed to send the mail. The DMARC record tells the recipient server if they should reject mail that fails the check.

Gmail will reject mail that does not have a valid SPF record; eventually most mail servers will follow suit.

An SPF record check the "Mail from" or Return-path address (NDR would go to this address), which may not be the same address in the From field in the message. DMARC checks the From address you see in the message.

If you use an Outlook.com custom domain, you should use the following SPF record. The "-all" tells the recipient server to reject the message if it was not sent from a server listed in the SPF record. Use "~all" for a softfail to tell the recipients server to accept the messages but mark it. This may result in the message going into the Junk mail folder.
v=spf1 include:outlook.com -all

If your custom domain uses another mail server, use this website to generate an SPF record for your domain:
SPF Wizard - SPF Generator DNS tool

A basic DMARC record either rejects or quarantines messages but can include addresses were reports are sent to and list what percentage of mail to apply the policy to.
v=DMARC1; p=quarantine
v=DMARC1; p=reject

A third authentication method stored in a DNS record is DKIM. This is a certificate on the outgoing server that helps to prevent spoofing. However, these cannot be set up on custom domains hosted in Outlook.com or on most mail servers. If your mail server does not configure this for you, don't worry about it.
How to use DKIM for email in your custom domain | Microsoft Learn

Workaround for Mac and Yahoo Syncing

While we're waiting for a fix for the issue where Yahoo accounts constantly sync in legacy Outlook for Mac, one user came up with a workaround: never delete or move messages in Outlook.

The user added the account to Apple Mail and he uses it to delete or move messages. While it's an extra step, if you prefer using legacy Outlook and don't like the New Outlook for Mac or Apple Mail, it is a tolerable workaround.

And no, no word yet on when this is expected to be fixed.

Microsoft support article on the issue: IMAP Yahoo and AOL accounts might experience issues with re-syncing folder content - Microsoft Support

Type / to insert files and more

A user asked "Microsoft added a feature where typing a slash (/) triggers a pop-up listing attachments you can add to the message. How can I turn this off? I need to write slashes a lot in my emails and its annoying."

That feature cannot be disabled at this time, but like the @mention feature, if you just keep typing, the attachment menu will go away. ESC key will also close it. (And yes, it is annoying.)

If you are using Outlook Pre, go to Help > Feedback to leave feedback on the option.

Missing Calendar in iCloud Add-in

In my last issue, I mentioned the iCloud Add-in from the Windows Store doesn't sync the calendar. Apple is aware of the issue, but I don't have any information on when this will be fixed but check for updates in the Windows store if you do not have updates installed automatically.

Installing the older iCloud downloaded from Apple solves the problem for most people. Get it here:
iCloudSetup.exe from Apple

Some users said the iCloud download from Apple would not install in Windows 11. In this case, GSyncIt is a good option to use in place of the iCloud add-in. It's free (with nag screens) if you only have one calendar to sync. It syncs with iCloud (and more) and does not use a separate data file, so you can use the calendar in the To-Do Bar.