Thanks for that info! It’s just what I needed!
> On Dec 7, 2021, at 8:35 PM, dove...@ptld.com wrote:
>
>
>>
>> Basically I want the server to check if the message being sent is encrypted
>> with OpenGPG and either proceed or reject the message based on that criteria.
>
>
> Postfix is your submission service so i think best to look that direction. If
> there is a header you can check for (if the header exist then allow sending)
> then postfix has header checks regexp/pcre that would be simple enough to
> setup.
>
> On the more complex side, postfix also supports policy servers you can write
> as a script (php, perl, python, etc) or you can go full on milter.
>
>
> http://www.postfix.org/header_checks.5.html
> http://www.postfix.org/SMTPD_POLICY_README.html
> http://www.postfix.org/postconf.5.html#non_smtpd_milters
