On Fri, 15 Apr 2022, Fourhundred Thecat wrote:
I am receiving spam emails, where the "to:" line is entirely missing in the email header.[...] Are there any legitimate cases where "to:" might be missing?
Many e-mails are sent to "BCC" lists, so they have no To: header (or have one with "undisclosed-recipients").
So I'd be careful with rejecting/filtering only based on that.
