Hello, I am receiving spam emails, where the "to:" line is entirely missing in the email header.
The header has "X-Original-To:" and "Delivered-To:", but no "to:" line. I have pasted the header here: https://ctxt.io/2/AABg30FRFQ How could I block such emails? Can I use header-check for this? Are there any legitimate cases where "to:" might be missing?
