Microsoft changes

laura
Industry
September 20, 2017

There’s been quite a bit of breakage and delivery failure to various Microsoft domains this month. It started with them changing the MX for hotmail.co.uk, then the MX for hotmail.fr… and both these things seem to have broken mail. I also saw a report this morning that some of the new MXs have TLS certificates that don’t match the hostnames.

What’s going on?

Historically, Microsoft had two completely separate commercial mail systems, their free webmail and a hosted enterprise solution. The free mail systems started when MS purchased Hotmail, evolved into Live and then eventually Outlook. The enterprise solution is currently Office365. It, too, started off when MS purchased a filtering company and then evolved it into Office365.
A few years ago Microsoft decided they no longer wanted two email systems. So they were going to migrate both to the same back end.

That was 2 years ago…

Yes. Much of the backend stuff has been moving around behind the scenes over the last 2 years. Recently, though, they’ve been deploying new MX records for some of the regional Hotmail domains.

Why should we care?

Well, all things being equal we shouldn’t. But, y’know, nothing about email can ever be easy. On Sept. 1, 2017 a number of people started reporting that all their mail to hotmail.co.uk was bouncing with user unknown messages. Even addresses that were known live. That’s when some folks noticed that the MX records had updated from mx[1-4].hotmail.com to *.olc.protection.outlook.com.
Based on some of the discussions surrounding the change, Hotmail intended to make this change quietly and let the old and new MXs run in parallel. But, spammers had to ruin it. There were so many senders that didn’t update their MX records MS decided to set the old mail servers to reject all mail to hotmail.co.uk. This broke a bunch of stuff with senders, particularly for those who cache MX records for a very long time.

They fixed it.

It appears most senders / ESPs got the message and updated their MX records. MS, to their credit, realized this wasn’t an ideal situation and adapted their transition process. It appears hotmail.fr is the next regional domain to move to the new MX. Instead of swapping out all of the records, MS has added *.olc.protection.outlook.com to the MX records for hotmail.fr. Mail to hotmail.fr is being handled by both the old mx[1-4].hotmail.com and the new *.olc.protection.outlook.com servers. I expect that they’ll phase out the old ones at some point.

Mostly.

Of course, the only reason I know the changes have happened at hotmail.fr is because I’ve seen some folks mentioning problems with sending to those domains. So not everything is wonderful here. I don’t have many details on what the symptoms are, but if you’re seeing some level of problems to hotmail.fr it’s possible it’s them and not you.
There was also a report on the mailop list today that there is an issue with the TLS certificates on the new MX domains – the server names don’t match. This is minor, but may cause TLS to fail until they fix it.

What now?

Microsoft is undertaking a major infrastructure upgrade, without taking down any services. It’s not going to happen as smoothly or as transparently as anyone wants it to. The issues we’ve seen so far are all pretty minor given the scope of the project. If we can get through the rest of this changeover with this level of hiccups we should all be thankful.
Do be aware that things might change and delivery might be erratic until the changeover is finished. Just keep sending good mail and give them the space to work things out on their end. Even though in the short term this might drive up the consumption of antacids, I think long term, this is going to be a win.

Microsoft deprecating SmartScreen filters

At the beginning of the month Microsoft announced that they were deprecating the SmartScreen filters used by the desktop Microsoft mail clients. These are the filters used in Exchange and various version of Outlook mail. This is yet further consolidation of spam filtering between the Microsoft free webmail domains, Office365 hosted domains and self hosted Exchange servers. The online services (hotmail.com, outlook.com, Office365, live.com, etc) have been using these filters for a while. The big change now is that they’re being pushed down to Exchange and Outlook users not hosted on the Microsoft site.
EOP was developed for Outlook.com (and friends) as well as Office365 users. From Microsoft’s description, it sounds like the type of machine learning engine that many providers are moving to.
Microsoft has published quite a bit of information about these filters and how they work on their website. One of the best places to start is the Anti-spam Protection FAQ. Something senders should pay attention to is the final question on that page: “What are a set of best outbound mailing practices that will ensure that my mail is delivered?” Those are all things deliverability folks recommend for good inbox delivery.
Poking around looking at the links and descriptions, there is a host of great information about spam filtering at Microsoft and how it works.
A page of note is their Exchange Online Protection Overview. This describes the EOP process and how the filters work.

Ask Laura: Is the SmartScreen Filter Really Smart?

Filtering more than spam

The obvious application of machine learning for email is to send spam to the junk/bulk folder. Most services use some level of machine learning for filters. Places like Gmail have extensive machine learning filters to filter spam and unwanted mail away from their users.
Some organizations are taking the filtering process a step further. Almost every mail client more advanced than PINE has the ability for users to create rules to sort mail into folders. Late last year, Office 365 rolled out a feature, Clutter that tracks how a user interacts with mail and filters unimportant mail. This allows each user to have their own filters, but without the overhead of having to create the filters.
The Clutter engine looks at both how the user interacts with mail and things it knows about the organization. For example, if Exchange is tied into Active Directory, then mail from a manager will be prioritized while mail from a co-worker may end up in the clutter folder.
Email is a critical business tool. A significant number of companies rely on email for internal and external communication. Many users treat their inbox as a todo list, prioritizing what they work on based on what’s in their mail box. Despite the needs of users, the mail client hasn’t really changed.
Over the last few years, we’ve seen different online services attempt to build a more effective email client. Some of these features were things like tabs and priority inbox at Gmail. Microsoft created the “sweep” feature for Outlook/Hotmail users to manage inbox clutter. Third parties have created services to try and improve the mailbox experience for their users.
Many of the email filters, up to this point, have really been focused on protecting users from spam and malicious emails. Applying that filtering knowledge to more than just spam, but to the different kinds of emails makes sense to me. I’ve always had a fairly extensive set of filters, initially procmail but now sieve, to process and organize incoming mail. But I kinda like the idea that my mail client learns how I filter messages and do the right thing on its own.
I’d love to see some improvements in the mail client, that make it easier to manage and organize incoming email. It remains to be seen if this is a feature that takes off and makes its way to other clients or not.