SMTP config for docker installation, add IP range to avoid "relay access denied"

[rikrdo89]

I would suggest adding to the smtp-email.rst documentation the need to specify the IP range 192.168.0.0/24 to the email server, because the docker installation does not use the standard docker 172.16.0.0/12 IP range. Otherwise, you will get a lot of relay access denied errors.

For postfix, that would be something like this (under /etc/postfix/main.cf): mynetworks = 127.0.0.0/8, 172.16.0.0/12, 192.168.0.0/24

Also dont forget to open port 25 on your firewall.

[cwarnermm]

Thanks, @rikrdo89, for your documentation suggestion. The next step for this issue is to technically review the details you've provided with Engineering.

[cwarnermm]

@nab-77 - This may be something to consider incorporating in the upcoming Docker installation docs update.

[yesbhautik]

Needed to create file? If yes then i can start working on it.

[cwarnermm]

Docs impact note: https://docs.mattermost.com/configure/smtp-email.html#smtp-email-setup