Spam Resource: Reference: Proton Email Domains

Al Iverson just posted a brilliant write-up on Spam Resource:

Proton (previously known as ProtonMail) is a “privacy and digital freedom” focused company based in Switzerland whose main offering is Proton Mail, offering end-to-end encryption, the promise of Swiss data security laws applying to oversight of your data, features to protect users from sender tracking, and more.If you’re looking to special case how you send mail to Proton’s subscriber base, for purposes of list segmentation, MTA throughput settings, or something similar, you’ll need to know all of Proton’s email domains.Their primary email domains are:proton.meprotonmail.compm.meprotonmail.ch The also host mail for various custom domains. Of the top 10 million domains, they host mail for just over six thousand email domains. To find those, look for domains that have an MX record pointing to “mail.protonmail.ch” or “mailsec.protonmail.ch.”

More here: Reference: Proton Email Domains