Gmail FBL update

Last week Gmail started contacting ESPs that signed up for their new FBL with more information on how to set up mailings to receive FBL emails.
One of the struggles some ESPs are having is the requirement for DKIM signing. Many of the bigger ESPs have clients that sign with their own domains. Gmail is telling these ESPs to insert a second DKIM signature to join the FBL.
There are a couple reasons this is not as simple or as doable as Gmail seems to think, and the challenges are technical as well as organizational.
The technical challenges are pretty simple. As of now, not all the bulk MTAs support multiple signatures. I’ve heard that multiple signatures are being tested by these MTA vendors, but they’re not in wide use. This makes it challenging for these ESPs to just turn on multiple signatures. For ESPs that are using open source software, there’s often a lot of customization in their signing infrastructure. Even if they have the capability to dual sign, if they’re not currently using that there is testing needed before turning it on.
None of the technical challenges are show stoppers, but they are certainly show delayers.
The organizational challenges are much more difficult to deal with. These are cases where the ESP customer doesn’t want the ESP to sign. The obvious situation is with large banks. They want everything in their infrastructure and headers pointing at the bank, not at their ESP. They don’t want to have that second signature in their email for multiple reasons. I can’t actually see an ESP effectively convincing the various stakeholders, including the marketing, security and legal staff, that allowing the ESP to inset a second signature is good practice. I’m not even sure it is good practice in those cases, except to get stats from Gmail.
Hopefully, Gmail will take feedback from the ESPs and change their FBL parameters to allow ESPs to get information about their customers who sign with their own domain.

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Gmail shows authentication data to the recipient

Yesterday Gmail rolled out some changes to their interface. One of the changes is that they are now showing end users authentication results in the user screen.
It’s really the next step in email authentication, showing the results to the end user.
So how does Google do this? Google is checking both SPF and DKIM. If mail is authenticated and the authentication matches the from address then they display the email as:
mail from steve to me
If we click on “details” for that message, we find more specific information.
full details of message showing signing domain and spf domainIn this case the mail went through our outgoing mailserver to gmail.
Mailed-by indicates that the message passed SPF and that the IP address is a valid source of mail from wordtothewise.com.
Signed-by shows the domain in the DKIM d=. In this case, we signed with the subdomain dt.wordtothewise.com. That’s what happens when you sign using the domain in the From address (or a subdomain of it).
For a lot of bulk senders, though, their mail is signed using their ESP’s domain instead.  In that case Gmail shows who signed the mail as well as the from address.

And when we click on “details” for that message we see:
3rd party signature detailsThis is an email from a sender using Madmimi as an ESP. Madmimi is handling both the SPF authentication and the DKIM authentication.
As an aside, this particular  sender has a high enough reputation that Gmail is offering me an unsubscribe option in their interface.
Gmail is distinguishing between first party and third party signatures in authentication. If the mail is authenticated, but the authentication appears to be handled by a separate entity, then Gmail is alerting recipients to that fact.
What does this mean for bulk senders?
For senders that are signing with a domain that matches their From: domain, there is no change. Recipients will not see any mention of your ESP in the headers.
However, if you are using an ESP that is signing your mail with a domain they own, then your recipients will see that information displayed in the email interface. If you don’t want this to be displayed by Gmail, then you will need to move to first party signing. Talk to your ESP about this. If they’re unsure of how to manage it, you can point them to DKIM Core for an Email Service Provider.
Gmail blogpost about the changes
Gmail help page about authentication results

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Google offers a number of solutions for users, including the ability to add 2 factor authentication to your Gmail account. I strongly recommend anyone who uses Gmail to do this.
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