Is there an authoritative source of all email domains and where they fit into the IP warming "domain" buckets?

Question

Is there a list somewhere that lists out the IP warming buckets (say, Yahoo/AOL, Gmail, Comcast, AT&T, etc.) and all possible email domains and which bucket they fit into? For example: the overarching Microsoft IP warming bucket consists of @live.com, @microsoft.com, @hotmail.com, and more.

Answer 1

I am not aware of any list, but typically you have around 10 - 15 large domains worth monitoring. Once you get down into the range of around 1000 addresses, it's ok to miss a domain or two, when making up a "bucket" the volume of such a domain won't skew your segmentations too much or put reputation building at risk.

So let's say you have around 30, worst case, meaning that the following is pretty practical and not much of a big data exercise :). You can run pretty much any domain where you have a suspicion against a tool that tells you about its owner and you will get a pretty good picture of who is on which infrastructure:

https://mxtoolbox.com/SuperTool.aspx

This bottom up search, done for a few dozen domains, is probably better than a top down list, as domain ownership is a pretty raw data point, meaning it won't get much more "authoritative" than this. You can probably trust a snapshot of this more than any curated source at that given time.

Try entering msn.com, live.com, hotmail.com and you will get Microsoft Corporation.

Indeed, those domains' behavior can be monitored through Microsoft SNDS, so very plausible.

Try aol.com, yahoo.com and ymail.com and you will get Oath Holdings.

Indeed, in our monitorings, we've found those domains to apply the exact same throttling patterns at the same time, so again: very plausible.

Works internationally, I did this in markets like Poland where I have no affiliation whatsoever and it definitely helps paint a picture.