Does any e-mail service allow maintaining a large blacklist (>=5000 addresses/domains)?
Why, for what requirement?
To save e-mail addresses from a “subscription bomb”. Accounts were targeted and signed up for thousands of newsletters, retail catalogs, etc. Inboxes are flooded daily so without a practical solution, years held long term e-mail addresses would have to be given up.
Probably not solutions
- Microsoft’s e-mail service. It seems (same for O365 or Outlook.com) to be limited to 1000 blocked users and domains regardless of the plan chosen.
- I already have a scrubbed clean list to be blocked (unique addresses/domains only) as a text file. The list size seems to have tapered, which is why I think it’s solvable, not infinite.
- Spam tools using Bayesian ratings and/or machine Learning. The attacker simply signed up accounts to receive tons of e-mail. A lot from normal businesses that shouldn’t be flagged.
- Just discovered Sieve Scripts. It seems not many e-mail web services support them, and their limits are not well documented for given services.
- Add-ins/Plugsins. Some exist for web e-mail services and can run server side (so all clients benefit). Surprised to find no simple add-in to do this, at least in the MS add-in store and with brief googling. KuTools seemed to have potential but was actually damaging (another story)
Fastmail.com supports sieve scripts but it’s no guarantee, waiting to hear back on detailed limitations
Really don’t care to run my own e-mail server, less practical than it seems I would guess
Requirement wouldn’t grow beyond 5000. Seems the attack was large but finite