Comment by immibis
2 months ago
99.9% of spam is not active circumvention of blocks. It comes from so many sources you can't block them, but they are true different sources and not a block circumvention technique. That's why we decided to come down with the biggest hammer on every single source.
That doesn't match my experience at all. If I disable filtering what I see is a slew of ephemeral domains. Without DMARC I'm sure they would instead be official looking and fake.
> It comes from so many sources you can't block them,
Nonsense. If it were really countless fixed sources then a centralized domain blacklist would be sufficient. The issue is that the sources - both domain and IP - are aggressively rotated and even spoofed whenever possible.
That's how it looks now, in a world of ubiquitous spam blockers. Originally, it was each company sending you a few pieces of spam from a legitimate address.