listen25.sh

# listen on port 25 and notify on slack if the program tries to send mail through

msg2slack() {
  read MESSAGE
  echo "PID: $$"
  echo "$MESSAGE"
  msg="connection attempt to port 25 on $(cat /etc/hostname):\n$MESSAGE"
  $DETECTMAIL_SLACK_URL && curl -X POST -H 'Content-type: application/json' --data "{\"text\":\"$msg\"}" $DETECTMAIL_SLACK_URL
}


socat -u tcp-l:25,fork system:msg2slack