Title: Configure OpenSMTPD to relay on a network | |
Author: Solène | |
Date: 29 October 2018 | |
Tags: openbsd highlight opensmtpd | |
Description: | |
With the new OpenSMTPD syntax change which landed with OpenBSD 6.4 | |
release, changes are needed for making opensmtpd to act as a lan relay | |
to a smtp server. This case wasn't covered in my previous article | |
about opensmtpd, I was only writing about relaying from the local | |
machine, not for a network. Mike (a reader of the blog) shared that it | |
would be nice to have an article about it. Here it is! :) | |
A simple configuration would look like the following: | |
listen on em0 | |
listen on lo0 | |
table secrets db:/etc/mail/secrets.db | |
action "relay" relay host smtps://[email protected] auth | |
<secrets> | |
match from local for any action "relay" | |
match from src 192.168.1.0/24 for action relay | |
The daemon will listen on em0 interface, and mail delivered from the | |
network will be relayed to remote-smtpd.tld. | |
For a relay using authentication, the login and passwords must be | |
defined in the file **/etc/mail/secrets** like this: `myrelay | |
login:Pa$$W0rd` | |
[smtpd.conf(5)](http://man.openbsd.org/smtpd.conf) explains creation | |
of **/etc/mail/secrets** like this: | |
touch /etc/mail/secrets | |
chmod 640 /etc/mail/secrets | |
chown root:_smtpd /etc/mail/secrets |