[Dovecot] Server-side sieve for client-side copies

[Eduardo M KALINOWSKI]

Daniel L. Miller escreveu:
> My understanding is that sending a message from a client (use 
> Thunderbird for simplicity of this conversation) is performed via 
> SMTP.  Saving a copy into a sent folder is performed via IMAP (hence 
> the multiple transfers to the server).  Now that I've laid a 
> background - let's make it Dovecot specific.  I don't know how 
> "behind-the-scenes" Dovecot performs the act of saving mail messages 
> that it receives from IMAP, instead of SMTP.  Specifically, if I'm 
> using sieve filters via deliver - can I setup a filter that will place 
> mail copies to specific recipients into specific subfolders?

Thunderbird and other mail clients store a copy of the sent message by 
using the IMAP APPEND command, which is a generic command to store a 
mail message (or anything else, if you are brave enough) in a mailbox.

Sieve filters are run for messages that are received via SMTP (usually 
from another host), and need to be saved in the user's mailbox. 
(Provided the mail server is configured to use dovecot's deliver to do 
that.)

So, in short, these are two very different processes, and no filtering 
is done for messages saved in a folder (such as Sent).