On 19/01, Steve Engledow wrote:
I'll have a poke around and post back if I figure out what's up.
Well, thanks to Noodles for figuring out what it was.
Way back when Terry Pratchett went and popped his clogs, I jumped on the bandwagon of [adding Clacks headers](http://www.gnuterrypratchett.com/) to my outgoing mail.
Unfortunately, the instructions at http://www.gnuterrypratchett.com/#postfix mean that the X-Clacks-Overhead header gets added even to incoming messages and even to the headers of individual parts of MIME messages. This means postfix was modifying the message on the way in and the signature was then invalid.
Unfortunately, I can't find a good way to get postfix to insert a header just on the way out and just in one place so I'll have to drop that for now. Or maybe just get mutt to do it for me.
Steve