SMTP Tiny List Manager

A tiny email list manager for OpenSMTPD.

Dependencies

• doas
• entr
• rset

Configuration

/etc/doas.conf

permit nopass admin as root cmd cp args tmp/members.new /etc/mail/members
permit nopass admin as root cmd rsub args /etc/mail/aliases
permit nopass admin as root cmd smtpctl args update table aliases
permit nopass admin as root cmd smtpctl args update table members

/etc/mail/smtpd.conf

smtp max-message-size 1M

table aliases file:/etc/mail/aliases
table members file:/etc/mail/members

filter "add_list_headers" proc-exec "/usr/local/libexec/smtpd/add_list_headers.awk"

listen on localhost port 25
listen on egress inet4 tls pki letsencrypt filter "add_list_headers"

action "local" maildir "%{user.directory}/mail" alias <aliases>
action "outbound" relay helo scriptedconfiguration.org

match from any for rcpt-to "[email protected]" action "local"
match !from mail-from <members> for domain "scriptedconfiguration.org" reject
match from any for domain "scriptedconfiguration.org" action "local"
match from local for local action "local"
match from local for any action "outbound"

Installation

for dir in bin etc tmp log; do
    install -d -o admin /home/admin/$dir
done
mkdir /usr/local/libexec/smtpd
install -m 755 -o admin process-messages.sh /home/admin/bin/
install -m 755 add_list_headers.awk /usr/local/libexec/smtpd/
install -m 755 read_message.awk /usr/local/libexec/smtpd/

Verification

telnet scriptedconfiguration.org 25

EHLO vm.eradman.com
MAIL FROM: <[email protected]>
RCPT TO: <[email protected]>
RSET
QUIT

This should return one of two responses

250 2.1.5 Destination address valid: Recipient ok
550 Invalid recipient: <[email protected]>

Caveats

• Multiple lists not supported
• Two-step verification not implemented