Allow local development server to send email via Mailcow

surfingjoe

Well, I tried the following:

White listing the IP address of the development server which is in the same network as the server which is running Docker for Mailcow.
Using “Docker exec -it <postfix container> /bin/bash” and edit /etc/postfix/main.cf and add local subnet as follows “mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128 192.168.50.0/24”. I suspect that isn’t working because docker containers are running on internal networks and I suspect does not route to my local network.

I see my development server properly communicating to the domain in Mailcow within Development Server’s Postfix logs. I also see mailcow postfix logs, mailcow rejecting the Dev Server’s IP address “Client host rejected: Access denied;”

How can I allow local Dev Server to send mail to Local Mailcow’s Domain?

I should also point out that ultimately, I would like to use Mailcow as a relay for apps in the local network to send as users within the domain for such services as notification of monitoring issues, and Web Server Forms send functions, etc.

ETNyx

You can try to set up your development server as authenticated client (relay). You can use Postfix, important part of your config could be like this

##/etc/postfix/main.cf
...

# do not accept connection from outsite this instance is local only
inet_interfaces = loopback-only
inet_protocols = all

# your mailcow that will do final delivery
relayhost = your.mailcow.ltd

# log to mailcow as user
smtp_sasl_auth_enable = yes
# how to log
smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd
# some securty settings,...
smtp_sasl_security_options = noanonymous
smtp_use_tls = yes
smtp_tls_mandatory_ciphers = high
smtp_tls_mandatory_protocols = !SSLv2, !SSLv3, !TLSv1, !TLSv1.1
smtp_tls_CAfile = /etc/ssl/certs/ca-certificates.crt
....

##/etc/postfx/sasl_passwd
# server user:pass (how to log)
your.mailcow.ltd username:password

some commands to finish

chmod 600 /etc/postfix/sasl_passwd
postmap /etc/postfix/sasl_passwd
service postfix reload
# test it, every mail send by system mail function should by relay to your mailcow
echo 'test' | mail -s 'test' you@example.com

harper89

Have you checked Docker’s network configuration and Mailcow’s SMTP relay settings for these adjustments?