Quoting Dave Evans:
> As it happens I'm currently trying to concoct a recipe for rewriting Message
> IDs - not to make them more FQDN-ish, but to make them less
> spammer-harvestable. Thunderbird (and other MUAs too for all I know)
> generates Message IDs that end in "@<domain of your email address>", which
> spammers like to then treat as email addresses.
Ha... I noticed spam runs on my msgids used as rcpt a while ago. So
instead of rewriting msgids (they are already out, anyway) I block them:
condition = ${if match
{$local_part}{\N(?i)^[0-9a-f]{8}\.[0-9a-f]{7}$\N}}
(actually, I defer/greylist them, so no legit mail is lost.)
