postfix for raspi info

 I just installed Postfix on multiple raspis to be informed about updates, problems etc.

Any suggestions on how this could be done easier by e.g. collecting would be very much appreciated.

I started of with:

sudo apt install postfix:

• Setup as satellite machine
• Hostname unchanged
• Relay or smarthost: put in your smtp
• Everythin else default.

After that I've updated my /etc/aliases to reroute everything towards root and then towards my external mail adress:

postmaster:    root

nagios: root

root: admin@yourdomain.com

in the postfix Config file: /etc/postfix/main.cf I added:

smtp_sasl_auth_enable = yes

smtp_sasl_security_options = noanonymous

smtp_sasl_password_maps = hash:/etc/postfix/sasl_password

sender_canonical_maps = hash:/etc/postfix/sender_canonical

smtp_tls_security_level = encrypt

The  meaning of sender_canonical  is not clear as it seems redundant to the aliases:

www-data admin@yourdomain.com

root admin@yourdomain.com

the sasl_password file needs the input of your external relay or smarthost:

smtpserver:25  user:password

Be sure, the file ist only readable by its owner.

now:

sudo newalias    --> gets the aliases updated

 sudo postmap hash:/etc/postfix/sasl_password  && sudo postmap /etc/postfix/sender_canonical --> gets the files merged into postfix

sudo systemctl restart postfix -->  start with new config

If everything works you should be able to do this:

echo Hello!  Test! | mail -s Testmail admin@yourdomain.com

If it does not work due to the encryption or auth because missing Mech:

https://serverfault.com/questions/1008119/postfix-error-sasl-authentication-failed-cannot-authenticate-to-server-no-mec

try to install:

apt install libsasl2-modules