@cs.stanford.edu email changes

Feb 1, 2024


e-mail forwarding change due to DMARC enforcement from gmail.com, yahoo.com, outlook.com

Users affected

CS accounts that forward their @cs.stanford.edu e-mail to domains not managed by CS

Action required

none, but please note your From lines will look differently


What's going on is that major e-mail providers such as Yahoo, Hotmail, Gmail, etc., along with governmental entities are now embracing an anti-spam/anti-phishing technology called DMARC. One aspect of DMARC is that it breaks e-mail forwarding. Most @cs.stanford.edu accounts use forwarding. Gmail and Yahoo have announced they will begin rolling out outright rejection of messages which fail DMARC starting February 2024.

We have been searching for ways to mitigate the problem with forwarding and with the help of several dozen faculty, staff, student, and alumni volunteers have had success in getting messages reliably delivered.

In order to pass DMARC alignment checks, we need to modify the From line of the message. For example, a message from an English colleague to a CSID named 'pbritt' would have the following From line:

From: Alan Turing turing@enigma.uk

If CSID 'pbritt' forwards their email outside of Stanford, that From line will be replaced with:

From: "Alan Turing turing@enigma.uk" <pbritt-forward.cs.stanford.edu>

The original sender's address is also preserved in a `Reply-To:` header so that a correct address is generated for a reply to the message.

Modifications to the `From:` line may cause issues with displaying the sender in some of the myriad of e-mail clients. Furthermore, the change may break some of the existing e-mail filters you may have set up. However, resetting the e-mail origin to a CS server and changing the From line is currently the only way to ensure e-mail delivery.

This is intended to be a short-term amelioration of DMARC issues to improve e-mail delivery while we add support to our e-mail servers for an experimental chain-of-custody protocol named ARC which Google et al say will satisfy them. If ARC succeeds, we will then stop modifying `From:` lines. We currently do not have an ETA for ARC implementation.

As always, if you have questions or encounter problems, open a ticket at https://support.cs.stanford.edu or email action [at] cs.stanford.edu.

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