Simple mail send on Ubuntu

Question

I have been struggling with mail function in Ubuntu. My goal is to send a test email from a terminal with a command:

echo "msg" | mail -s subject [e-mail].

I have tried to install sendmail, but figured out that it could send if I rely on rely server(google smtp). I have tried to install exim4, but in logs provides this data:

2015-11-10 19:09:03 1ZwCPm-00015C-TP <= root@localhost U=root P=local S=788  
2015-11-10 19:09:03 1ZwCPm-00015C-TP ** localhost@localdomain <root@localhost>: Unrouteable address  
2015-11-10 19:09:03 1ZwCPm-00015C-TP => /var/mail/mail (root@localhost) <root@localhost> R=mail4root T=address_file 

2015-11-10 19:09:03 1ZwCPn-00015H-4o <= <> R=1ZwCPm-00015C-TP U=Debian-exim P=local S=1607 

2015-11-10 19:09:03 1ZwCPm-00015C-TP Completed

I have no experience before configuring mail servers. Is it possible to do such action without having FQDN and domain name? Where do I start my investigation on such topic?

Answer 1

Install the postfix package and edit your configuration (usually at /etc/postfix/main.cf) to be:

relayhost = [smtp.gmail.com]:587
smtp_use_tls = yes
smtp_sasl_auth_enable = yes
smtp_sasl_security_options = noanonymous
smtp_sasl_password_maps = hash:/etc/postfix/sasl/passwd

Now, create the /etc/postfix/sasl directory and create a file called passwd inside with this content:

[smtp.gmail.com]:587    [e-mail]:PASSWORD

Finally, use this command:

postmap /etc/postfix/sasl/passwd

Now, if you use the first syntax (which was correct), you should get your e-mail sent:

echo "msg" | mail -s subject [e-mail].