Domain

Sending domains and hostnames

Lots of times I see someone asking a question and they talk about their sending domain. And it’s sometimes not 100% clear which domain they mean by that – and when we’re talking about alignment and reputation it can make a difference. So here’s a list of (some of?) the different places a mailserver uses a domain.

Cousin domains

When I checked in on Facebook this morning there was a discussion from a couple people frustrated by cousin domains. I share their frustration.

Organizational Domain

We often want to know whether two hostnames are controlled by the same person, or not.

Back from MAAWG

Had an all too short trip to M³AAWG. It was great to see old friends and meet new folks. I have lots to talk about and a poll to get into the field once I get caught up on client work.

While I’m deep in the depths of my inbox, I thought I’d share a bit of insight into the question of new domain vs. subdomain that often comes up.

The long tail of domains

I frequently get clients telling me that they have about 15 (20, 30) major domains on their list, and then a long tail of domains with only a couple of recipients. If you sort simply by the left hand side of the @, that’s true.
When you’re sending email, it’s not just the domain in the email address that is important. Of equal importance is the MX. The MX is what actually handles the mail and where many filters are applied. Sorting by MX, instead of simply recipient domain, can identify that most of your small business clients are hosted at a particular provider. The number of subscribers behind that filter may be enough to push that filter into your top 10 or even top 5 recipient domains.
There’s a much smaller tail when grouping recipients by MX domain. It makes it much easier to understand where blocks are happening. I have even seen cases where clients didn’t realize they were blocked at a commercial provider because they only saw the “onesie twosie” domains as undeliverable. They missed a real problem with blocking because they were looking at the wrong data.
I sometimes get the side eye from some ISP folks if I use the term receiver (because, well, they’re senders as much as they are receivers). But I use receiver to help distinguish between the recipient domain and the actual domain handling the email.
When was the last time you looked at your delivery by filter or MX rather than by recipient domain? What did you find?

Domains need to be warmed, too

One thing that came out of the ISP session at M³AAWG is that domains need to be warmed up, too. I can’t remember exactly which ISP rep said it, but there was general nodding across the panel when this was said.
This isn’t just the domain in the reverse DNS of the sending IP, but also domains used in the Return Path (Envelope From) and visible from.
From the ISP’s perspective, this makes tons of sense. Some of the most prolific snowshoe spammers use new domains and new IPs for every send. They’re not trying to establish a reputation, rather they’re trying to avoid one. ISPs respond by distrusting any mail from a new IP with a new domain.

NetSol opts users into new $1850 security program

Network Solutions Auto Enroll Security

Yahoo now auctioning domain names

This summer Yahoo shook up the email ecosystem by publicly announcing they were recycling usernames. The shakeup wasn’t so much that they were recycling usernames, but that they did it in a way that compromised user information and account security. Any user that had an account tied to a recycled Yahoo account is at risk for having their PII leaked. Folks are still dealing with the fallout, both Yahoo and the companies who are trying to meet customer needs by sending emails and protect customer emails by not sending emails.
On top of that, Yahoo announced they’re selling off a number of domains that they’ve accumulated over the years. Some of these are pretty high value domains like webserver.com, sandwich.com and other real words.
I don’t think Yahoo used any of these domains for email, and even if they did any addresses should have bounced off years ago. Still, it does bring up some broader policy issues.
Many, many things online, from bank accounts to social media accounts to blog commenting systems treat email addresses as a unique identifier for that account. Many of these databases were developed with the underlying assumption that people wouldn’t change their email addresses and that it was a static value. This wasn’t a true assumption 10 years ago and it’s certainly not true now. This mistaken assumption is a problem, and one that more and more companies are going to have to address moving forward. This isn’t about email and it isn’t about delivery, it’s about simple data accuracy and hygiene.
Companies must start thinking and addressing email address impermanence. These issues are not going away.

Looking towards the future

I had the opportunity to go to a seminar and networking event hosted by Return Path yesterday evening. The topic was “Email trends in 2012” and it was presented by Tom Sather.
If any of you get the opportunity to go to a talk presented by any of the Return Path folks I encourage you to do so. They know their stuff and their presentations are full of good information.
One of the trends mentioned is the increase in reliance on domain reputation. It’s something I’ve been thinking about more and more recently. I wrote a little bit about it recently, but have focused more on the whole realm of content filtering rather than just domain reputation.
Domain reputation is where delivery is going. And I think a lot of senders are going to struggle with delivery as they find that IP reputation is not enough to get into the inbox.