Blocking Gmail

After putting a lot of effort into customizing Proxmox Mail Gateway to build the perfect anti-spam solution, I’ve recently restarted my PMG project with a completely new approach: As little customization as possible to remain updateable and upgradeable (and sometimes taking a harder approach than second-guessing every setting, because after all, it’s just for my own use). I may also share my findings with the community, but for now the first big decision I’ve made is to block anything that ends up being just spam. For this decision, I reduced the blocking level to a spam score of 5 on the SpamAssassin content scan (because I was able to keep it low and reduce it from 10 without additional checks that led to higher scores last time), and the second big thing (after years of deliberation) is to completely block all mail from Gmail (since ultimately only spam comes from there).

For the future, I may consider others, since SendGrid is also a big source of spam/phishing/cybercrime (and seems to have no interest at all in changing that).