After months of using MX Guarddog to filter spam coming to my public email (as detailed in my prior post Using Posteo with a Custom Domain), I had to find another service. While MX Guarddog was essentially free, it was ineffective. I was still receiving (and reporting) multiple spam emails in my inbox (curiously they mostly came on Monday mornings, I guess spammers have schedules too). I tried to work with support, but even after “adjusting” my filters, there was just too much spam.
Fortunately an alternative (albeit more expensive) service exists: Mailroute. The concept is the same; my domain’s MX records point at MailRoute, which quarantines the spam, and forwards the legitimate email. MailRoute is GDPR compliant, supports 2FA, has a free trial, and otherwise costs $30.00 a year. I have been using MailRoute since April 2018, and have only had to report 36 missed spam emails. This number might seem high, but with MX Guarddog it was 187 emails from October 2017 to April 2018, or ~0.99 spam/day, and Mailroute reduced that to ~0.26 spam/day, and this is tolerable (considering they block ~60 spam/day). I’ve only had a few false positives, which were easy enough to recover and whitelist.
The setup is quite simple: at your DNS provider, replace your MX
records with a single record pointing to mail.mailroute.net; add
your domain and user to Mailroute; and point Mailroute to your
forwarding provider (in my case, Gandi’s email service at
spool.mail.gandi.net). Then have your forwarding provider route to
your private Posteo email. No more spam with your custom domain
pointing at Posteo.
By the way, Posteo is still the best email provider available, despite their lack of direct support for custom domains.