Postfix for sending email only from localhost

1. Install Postfix and configure

   $ sudo apt-get update
   $ sudo apt-get install mailutils

   

   

   $ sudo systemctl status postfix

   
   ● postfix.service - LSB: Postfix Mail Transport Agent
      Loaded: loaded (/etc/init.d/postfix; bad; vendor preset: enabled)
     Drop-In: /run/systemd/generator/postfix.service.d
              └─50-postfix-$mail-transport-agent.conf
      Active: active (running) since {DATE}; 8min ago
        Docs: man:systemd-sysv-generator(8)
     Process: 24767 ExecStop=/etc/init.d/postfix stop (code=exited, status=0/SUCCES
     Process: 24796 ExecStart=/etc/init.d/postfix start (code=exited, status=0/SUCC
      CGroup: /system.slice/postfix.service
              ├─{PS_NUM1} /usr/lib/postfix/sbin/master
              ├─{PS_NUM2} pickup -l -t unix -u -c\
              └─{PS_NUM3} qmgr -l -t unix -u

2. Test

   $ echo "TEST BODY" | mail -s "TEST SUBJECT" account@email.server.com

3. Error

   Check /var/log/mail.err