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://myrelay@remote-smtpd.tld 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