rephrase before/after queue filtering for clarity

starting the listing with before/after queue filtering makes it easier to
scan through the document, especially if we refer to it with the same words
below.

Huge thanks to Daniela for suggesting the edit.

Signed-off-by: Stoiko Ivanov <s.ivanov@proxmox.com>
Reviewed-By: Aaron Lauterer <a.lauterer@proxmox.com>
This commit is contained in:
Stoiko Ivanov 2020-04-23 15:29:43 +02:00 committed by Thomas Lamprecht
parent bc1de76ea2
commit 1824eab9da

View File

@ -308,23 +308,23 @@ Before and After Queue scanning
Scanning email can happen at two different stages of mail-processing:
* During the SMTP Session after the complete message has been received (after
the 'DATA' command), known as 'before queue filtering'.
* Before-queue filtering: During the SMTP Session, after the complete message
has been received (after the 'DATA' command).
* After intially accepting the mail and putting it on a queue for further
processing, known as 'after queue filtering'.
* After-queue filtering: After initially accepting the mail and putting it on
a queue for further processing.
The former has the advantage that the system can reject a mail (by sending a
permanent reject code '554'), and leave the task of notifying the original
sender to the other mailserver. This is of particular advantage if the
processed mail is a spam message or contains a virus and has a forged
Before-queue filtering has the advantage that the system can reject a mail (by
sending a permanent reject code '554'), and leave the task of notifying the
original sender to the other mailserver. This is of particular advantage if
the processed mail is a spam message or contains a virus and has a forged
sender-address. Sending out a notification in this situation leads so-called
'backscatter' mail, which might cause your server to get listed as spamming on
RBLs.
The latter has the advantage of providing faster delivery of mails for the
sending servers, since queueing mails is much faster than analyzing it for
spam and viruses.
After-queue filtering has the advantage of providing faster delivery of
mails for the sending servers, since queueing mails is much faster than
analyzing it for spam and viruses.
If a mail is addressed to multiple recipients (e.g. when multiple addresses are
subscribed to the same mailinglist) the situation is more complicated: Your