Keyword based custom subject warning

[Benny Pedersen]

On 2022-03-07 12:23, Dominic Raferd wrote:
> On 07/03/2022 11:12, Damian wrote:
>>> apparently, our users are receiving emails containing links and /or 
>>> references to various publications, some of which are considered 
>>> 'predatory'. Emails usually contain ISSN (International Standard 
>>> Serial Number) and the idea is to scan the body of an email for the 
>>> ISSN and if it matches one on the 'blacklist', the subject of the 
>>> email should be prepended with some specific warning (other than 
>>> ***SPAM***).
>>> 
>>> We're already using Amavisd-new on our inbound SMTP server, so I 
>>> wonder if that would be possible with it?
>> 
>> This would have been a use-case for [1]. The corresponding Amavis 
>> feature is still unreleased, unfortunately.
>> 
>> [1] 
>> https://spamassassin.apache.org/full/3.4.x/doc/Mail_SpamAssassin_Conf.html#subjprefix
>> 
> Good call. But if Amavis is calling SA (which is normal) this feature
> in SA can still be used can't it? As Benny has pointed out, changing
> the subject will break DKIM signing, but that may not matter to OP.

dkim verify is done BEFORE breaking dkim, so not a problem, but it is if 
forwarding mails

forwarding hosts should only do ARC-Seal, ARC-Sign, BEFORE breaking dkim