Hello,
I'm using version 2.3.4.1 and I have a fairly simple setup based on a submission server where I run dovecot and a relay server with postfix. The relevant part of dovecot's config is as follows (sanitized):
hostname = submission.domain.local submission_client_workarounds = whitespace-before-path submission_relay_host = 192.168.1.1 <- postfix submission_relay_port = 25 submission_relay_trusted = yes
Postfix is configured as follows:
smtpd_authorized_xclient_hosts = 192.168.1.2 <- submission server
Everything apparently works as expected, meaning that I can correctly authenticate on the submission server and the email is relayed to postfix, where I can see the original MUA's IP correctly logged.
There is, however, a little problem with the client HELO string that is not being forwarded to postfix. Instead of having the MUA HELO, I see the submission server HELO, as shown in the following tcpdump taken on the postfix server:
220 postfix.domain.local ESMTP Postfix (Ubuntu) EHLO submission.domain.local 250-postfix.domain.local 250-PIPELINING 250-SIZE 10240000 250-VRFY 250-ETRN 250-STARTTLS 250-AUTH DIGEST-MD5 CRAM-MD5 NTLM PLAIN LOGIN 250-AUTH=DIGEST-MD5 CRAM-MD5 NTLM PLAIN LOGIN 250-XCLIENT NAME ADDR PROTO HELO REVERSE_NAME PORT LOGIN DESTADDR DESTPORT 250-ENHANCEDSTATUSCODES 250-8BITMIME 250-DSN 250 SMTPUTF8 XCLIENT ADDR=192.168.1.3 PORT=57116 LOGIN=riccardo-at-domain.local 220 postfix.domain.local ESMTP Postfix (Ubuntu) EHLO submission.domain.local 250-postfix.domain.local 250-PIPELINING ...
As you can see the first EHLO is correctly done with the submission server's hostname, but the subsequent one after XCLIENT is -still- the same hostname, while I was expecting that to be the one forwarded from the MUA, or possibly a "HELO=somethingelse" in the XCLIENT line.
I've looked almost everywhere and I couldn't find a way to make dovecot use the MUA's HELO string. The question I'm asking is if there is a way to have the MUA's HELO forwarded to the relay server in some way, or if this is a bug or an expected behaviour.
Thanks for any help you could give
-- Best regards, Riccardo Alfieri
Spamhaus Technology https://www.spamhaustech.com/