14 May
2021
14 May
'21
6:11 p.m.
Vielen Dank. (Google Translate)
LMTP seems the way to go.
-----Original Message----- From: dovecot dovecot-bounces@dovecot.org on behalf of Heiko Schlittermann hs@schlittermann.de Organization: schlittermann -- internet & unix support Date: Friday, May 14, 2021 at 11:08 To: dovecot@dovecot.org Subject: [EXTERNAL] Re: Separating Dovecot and Postfix
Hi,
White, Daniel E. (GSFC-770.0)[NICS] <daniel.e.white@nasa.gov> (Fr 14 Mai 2021 14:37:15 CEST):
> I am struggling to update a very old set of mail servers.
> Some are supposed to be relays (MTAs by my understanding) while others are where the mailboxes live (MDA)
It depends on how your MTA hands-over the messages to the Mail Storage
Agend (MSA).
If both are on the same machine, in the same file system, there are
multiple methods:
- direct file system access: The MTA knows about the internal
structure of the MSA and writes directly to the (mostly
Maildir) mailboxes. This is considered bad practice.
- local delivery agent: `dovecot-deliver` read the message from standard
input and - as part of the MSA - it knows about the internal structure
and hides it from the MTA. This is good practice, but it may impose
permission issues.
- LMTP: The MTA uses a variant of the SMTP protocol to push the message
to the MSA, dovecot can listen on a Unix-Domain socket, as well as on
an INET socket, and serve as an LMTP server. This is IMHO the best
option, as it allows the best privilege separation, and addtionally
it allows an easy migration from having both (MTA, MSA) on the same
machine to separate machines.
If you have both (MTA, MSA) on distinct machines, then only LMTP is your
option. I'm pretty sure that Postfix can use LMTP over INET style network
connections. Depending on how you trust into your network, you should
consider using TLS for this connection.
Best regards from Dresden/Germany
Viele Grüße aus Dresden
Heiko Schlittermann
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