Bug#1125132: exim4: Cannot send email to smtp.themessagingco.com.au when using CGNAT address

[Arthur Marsh]

Package: exim4
Followup-For: Bug #1125132

Dear Maintainer,

*** Reporter, please consider answering these questions, where appropriate ***

   * What led up to the situation?

After trying what was suggested in:
https://unix.stackexchange.com/questions/729168/send-email-via-exim4-using-port-587
I was able to send outgoing SMTP mail to the smarthost on port 587

Maybe it should be documented that outgoing connections to the smarthost on 
port 25 may be blocked, and where to change the configuration to match what
the smarthost supports?

   * What exactly did you do (or not do) that was effective (or
     ineffective)?
   * What was the outcome of this action?
   * What outcome did you expect instead?

*** End of the template - remove these template lines ***


-- Package-specific info:
Exim version 4.99.1 #2 built 21-Dec-2025 07:00:57
Copyright (c) University of Cambridge, 1995 - 2018
(c) The Exim Maintainers and contributors in ACKNOWLEDGMENTS file, 2007 - 2025
Hints DB:
 Using sqlite3
Support for: Local_Scan Exim_filter Sieve_filter crypteq iconv() IPv6 GnuTLS move_frozen_messages TLS_resume DANE DKIM DNSSEC ESMTP_Limits ESMTP_Wellknown Event I18N OCSP PIPECONNECT PRDR Queue_Ramp SOCKS SRS TCP_Fast_Open
Lookups (built-in): lsearch wildlsearch nwildlsearch iplsearch cdb dbm dbmjz dbmnz dnsdb dsearch nis nis0 passwd sqlite
Authenticators (built-in): cram_md5 external plaintext
Routers (built-in): accept dnslookup ipliteral manualroute redirect queryprogram
Transports (built-in): appendfile/maildir/mailstore autoreply lmtp pipe smtp
Fixed never_users: 0
Configure owner: 0:0
Size of off_t: 8
Configuration file search path is /etc/exim4/exim4.conf:/var/lib/exim4/config.autogenerated
Configuration file is /var/lib/exim4/config.autogenerated
# /etc/exim4/update-exim4.conf.conf
#
# Edit this file and /etc/mailname by hand and execute update-exim4.conf
# yourself or use 'dpkg-reconfigure exim4-config'
#
# Please note that this is _not_ a dpkg-conffile and that automatic changes
# to this file might happen. The code handling this will honor your local
# changes, so this is usually fine, but will break local schemes that mess
# around with multiple versions of the file.
#
# update-exim4.conf uses this file to determine variable values to generate
# exim configuration macros for the configuration file.
#
# Most settings found in here do have corresponding questions in the
# Debconf configuration, but not all of them.
#
# This is a Debian specific file

dc_eximconfig_configtype='smarthost'
dc_other_hostnames=''
dc_local_interfaces='127.0.0.1'
dc_readhost='internode.on.net'
dc_relay_domains=''
dc_minimaldns='false'
dc_relay_nets=''
dc_smarthost='smtp.themessagingco.com.au'
CFILEMODE='644'
dc_use_split_config='false'
dc_hide_mailname='true'
dc_mailname_in_oh='true'
dc_localdelivery='mail_spool'
mailname:localhost
# /etc/default/exim4
EX4DEF_VERSION=''

# 'combined' -	 one daemon running queue and listening on SMTP port
# 'no'       -	 no daemon running the queue
# 'separate' -	 two separate daemons
# 'ppp'      -   only run queue with /etc/ppp/ip-up.d/exim4.
# 'nodaemon' - no daemon is started at all.
# 'queueonly' - only a queue running daemon is started, no SMTP listener.
# setting this to 'no' will also disable queueruns from /etc/ppp/ip-up.d/exim4
QUEUERUNNER='combined'
# how often should we run the queue
QUEUEINTERVAL='30m'
# options common to quez-runner and listening daemon
COMMONOPTIONS=''
# more options for the daemon/process running the queue (applies to the one
# started in /etc/ppp/ip-up.d/exim4, too.
QUEUERUNNEROPTIONS=''
# special flags given to exim directly after the -q. See exim(8)
QFLAGS=''
# options for daemon listening on port 25
SMTPLISTENEROPTIONS=''

-- System Information:
Debian Release: forky/sid
  APT prefers experimental
  APT policy: (1, 'experimental')
Architecture: amd64 (x86_64)

Kernel: Linux 6.19.0-rc5+ (SMP w/12 CPU threads; PREEMPT)
Kernel taint flags: TAINT_USER
Locale: LANG=en_AU.UTF-8, LC_CTYPE=en_AU.UTF-8 (charmap=UTF-8), LANGUAGE=en_GB
Shell: /bin/sh linked to /usr/bin/dash
Init: sysvinit (via /sbin/init)

Versions of packages exim4 depends on:
ii  debconf [debconf-2.0]  1.5.91
ii  exim4-base             4.99.1-1
ii  exim4-daemon-light     4.99.1-1

exim4 recommends no packages.

exim4 suggests no packages.

-- debconf information:
* exim4/drec: