Deferrals at Microsoft

If you’re seeing a lot of “451 4.7.500 Server busy. Please try again later” from Office365 this morning you’re not alone.

Microsoft are aware of the issue, and incident EX680695 says:

Current status: We’ve identified that specific IP addresses are being unexpectedly limited by our anti-spam procedures, causing inbound external email delivery to become throttled and delayed. We’re reviewing if there have been any recent changes to our anti-spam rules to understand why the IP addresses are being limited. In the meantime, we’re manually adding reported affected IP addresses to an allowed list to provide immediate relief.

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Microsoft changes

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.

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What's up with microsoft?

A c/p from an email I sent to a mailing list.
I think we’re seeing a new normal, or are still on the pathway to a new normal. Here’s my theory.
1) Hotmail made a lot of underlying code changes, learning from 2 decades of spam filtering. They had a chance to write a new codebase and they took it.
2) The changes had some interesting effects that they couldn’t test for and didn’t expect. They spent a month or two shaking out the effects and learning how to really use the new code.
3) They spent a month or two monitoring. Just watching. How are their users reacting? How are senders reacting? How are the systems handling everything?
3a) They also snagged test data along the way and started learning how their new code base worked and what it can do.
4) As they learned more about the code base they realized they can do different and much more sophisticated filtering.
5) The differences mean that some mail that was previously OK and making it to the inbox isn’t any longer.
5a) From Microsoft’s perspective, this is a feature not a bug. Some mail that was making it to the inbox previously isn’t mail MS thinks users want in their inbox. So they’re filtering it to bulk. I’ll also step out on a limb and say that most of the recipients aren’t noticing or caring about the missing mail, so MS sees no reason to make changes to the filters.
6) Expect at least another few rounds of tweak and monitor before things settle into something that changes more gradually.
Overall, I think delivery at Microsoft really is more difficult and given some of the statements coming out of MS (and some of the pointed silence) I don’t think they’re unhappy with this.

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OATH and Microsoft updates

I’ve seen multiple people asking questions about what’s going to happen with the Yahoo and AOL FBLs after the transition to the new Oath infrastructure. The most current information we have says that the AOL FBL (IP based) is going away. This FBL is handled by the AOL infrastructure. As AOL users are moved to the new infrastructure any complaints based on their actions will come through the Yahoo complaint feedback loop (CFL). The Yahoo CFL is domain based. Anyone who has not signed up for the Yahoo CFL should do so.
When registering you will need each domain and the selectors you’re planning on using. Yahoo will send an email with a confirmation link that needs to be clicked on within a short period of time in order to activate the FBL.
Microsoft’s SNDS program had an outage at the end of last week. That’s been fixed, but the missing data will not be back populated into the system. This has happened a couple times in the past. It seems the system gets a live feed of data. If, for some reason, the data is interrupted, then it’s gone and doesn’t get populated.

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