@mntmn @bleeptrack sadly you probably cannot build a plugin for a receiving mail server because it would break DKIM signatures. The outgoing server however could add stamps and the mail client then has to render the postmark depending on the mail header. But that would be complicated because it touches so many software projects. I think a client only solution would be the easiest (or you do the spam processing and afterwards deliberately remove the DKIM signature on the receiving server)
Now i want this ๐ itโs such a neat idea to bring back some of the โold daysโ. I remember decorating the envelopes was a thing too thatโs completely gone with electronic equivalents too.
@bleeptrack client seems like a good place, maybe mailservers can be allowed to add to the stamp. Would this be a generative thing based on string(s) in the header? That would be cool, like the 'received' header, it can be multiple and each adds to it. Hmm, could also use the 'received' header as a stamp modifier.
sending client inserts initial stamp string, receiving client generates stamp based on initial stamp string + all 'received' headers.
The stamps on a received mail should get semi-transparant post marks for each hop from the respective server. Could be generated from the mail header info.