More Email Hell

Checking in on our Bulk Email Server’s Bona Fides

As it so often happens with email delivery, we think everything is honky dory with our servers until we get a call from a customer who says either (a) they're not getting the emails from their Contact Us form, or (b) their own customers aren't getting the bulk emails they send out. Such was the call we received from Patrick, who has all email generated by the Contact Us form on his RocketFusion website forward to his Gmail address.

Generally we find that it's a particular ESP (Email Service Provider), such as Gmail, Hotmail, AOL or Yahoo, that is blocking our emails, or dropping them into the Spam or Junk folders. This happens from time to time if they receive a lot of email from us, and either many of the addresses in a particular customer's contact list are no longer good, or many of the recipients at a particular ESP click the "this is spam" button in their email interface. The latter happens the most with Yahoo and AOL.

I wrote about my travails in this area back in March of 2014, here: Ten-Days-of-Email-Hell

What has changed since I wrote that article is the following:

  • SSL secure email servers have become more important (we now support SSL on our personal email server)
  • DKIM has become required (every email domain we host now has DKIM signing)
  • Feedback Loops have become more available
  • DMARC has become more supported, and more services are injesting the reports and presenting them in a readable, understandable manner. More about that in another article.

Email Server Reputation Management

Of all the major ESPs, Microsoft (hotmail, msn, live) and AOL have provided reputation reporting tools for years.

  • Microsoft's SNDS: Currently our bulk email server has a reputation of Good. No reporting yet on our other server.
  • AOL's Postmaster IP Reputation Tool: Currently our bulk email server has a reputation of Neutral and our other server has a reputation of Good.

Yahoo continues to be unresponsive in terms of email server support, which is problematic because they're definitely one of the top emailed to domains. It's been like this since I started hosting email back in 2002. I mean, seriously guys... your verification tool is broken, and emails to support go unanswered.

Comcast has a Feedback Loop. Verizon provides no known reputation reporting. Still looking...

Feedback Loops

We have subscribed to all the Feedback Loops we can:

  • Comcast
  • AOL
  • Microsoft (hotmail, live, msn)
  • Gmail (read below)

Gmail Sets Up Reputation Reporting Tools

The good news is Gmail has now finally gotten into the reputation reporting game. Simply provide them the IP number of your email server, add a special verification code to your DNS file, and you now have access to all kinds of reporting on your server.

They also have created an interesting Feedback Loop tool. Once your server is registered with them, you simply have to add a special header, called Feedback-ID, to every email you send from your server, with the following information, and they'll give you all sorts of reports on your various email campaigns.

Feedback-ID: CampaignID : CustomerID : MailTypeID : SenderID

You can read more about the Feedback Loop tool on their website, but here it is in a nutshell:

The Feedback-ID header's value is read right-to-left...

  • SenderID is the sender's unique Identifier and can be used for overall statistics. We have set this to "RocketFusion."
  • MailTypeID is an Identifier for the type of mail (a newsletter vs. a product update, for example) and can be either unique or common across customers, based on how the sender wants to view the data. We have set this to "BulkSender" for all emails sent as a bulk email to your contact list, and "ContactEmail" for all emails generated when someone fills out your contact us form.
  • CustomerID is a unique customer Identifier. Each RocketFusion customer has their own unique identifier, so every email campaign they do can be grouped and reported on.
  • CampaignID is a campaign Identifier specific to the Customer, above, and is unique to each bulk email sent, so every email campaign can be scrutinized individually to see if it was considered spam by Gmail.

In the above case, Gmail would send the spam percentages for each of the 4 Identifiers independently, and show if they had an unusual spam rate. This is good information to know, and will be very helpful to combat grey-listing or black-listing our servers.


Well, let me tell you, I was excited. It took me all of ten minutes to implement everything Gmail has to offer, and have fully implemented their Feedback Loop system, shown above. 383 326 197 97 32 27 24
yahoo .com 5278
gmail .com 4639
comcast .net 4009
hotmail .com 2096
aol .com 1796
metrocast .net 630
msn .com 412
myfairpoint .net 308
verizon .net 173
live .com 147

This is important stuff, folks. Look at these two tables, left and right. The table on the left shows the number of per-domain email accounts on the most prolific bulk emailing customer we have (based in NH). They send out two emails a week to everyone in their database... nearly 12,000 customers altogether. Gmail accounts for 4,639 of those customers, a little over 1/3 of them all.

The table on the right shows our second most prolific bulk emailing customer (based in Western Mass). Gmail is their #1 sent-to domain. Yahoo is #2.

If Gmail were to start blocking all our emails, it would be devestating.

We will continue to try to get in to Yahoo's system, but until then, know that we're doing our best to stay on top of the email server issues.