Emails
Sending emails is important for a server. It allows it to notify you of various events (update pending, task failure, breach attempt…).
This guide will show you two different configuration options:
- Send only: Simple configuration. The server uses an external SMTP server to send emails. Use this if you want to just receive notification emails from a server.
- Complete: A complete email infrastructure with your own SMTP and IMAP server. Plus a webmail and the much needed spam filter.
Send Only
Install
$ sudo apt install exim4-daemon-light bsd-mailx
Configure
Edit file /etc/exim4/update-exim4.conf.conf
dc_eximconfig_configtype='satellite'
dc_other_hostnames=''
dc_local_interfaces='127.0.0.1; ::1'
dc_readhost='example.org'
dc_relay_domains=''
dc_minimaldns='false'
dc_relay_nets=''
dc_smarthost='smtp.example.org::587'
CFILEMODE='644'
dc_use_split_config='true'
dc_hide_mailname='true'
dc_mailname_in_oh='true'
dc_localdelivery='mail_spool'
Edit file /etc/exim4/passwd.client and add a line like
smtp.example.org:username:mYpa$$w0rd
Note: if smtp.example.org is a CNAME, you must use the destination of the CNAME in the passwd.client file.
$ host smtp.gmail.com
smtp.gmail.com is an alias for gmail-smtp-msa.l.google.com.
gmail-smtp-msa.l.google.com has address 74.125.206.108
gmail-smtp-msa.l.google.com has address 74.125.206.109
gmail-smtp-msa.l.google.com has IPv6 address 2a00:1450:400c:c04::6d
here you see on the first line that smtp.gmail.com is a CNAME (alias) to gmail-smtp-msa.l.google.com. In that case you can put *.google.com in the password file.
Finally, activate the new configuration using
$ sudo systemctl reload exim4.service
Test
$ echo "test" | mailx -s "test" root
You should receive the email in your mailbox
Complete
Want to get rid of Google and have your private emails be really private? Building your own mail server is the solution.
Warning: Getting your own mail server is rewarding and fun, however it's harder and more time consuming than typical sysadmin tasks like installing a webserver. If done incorrectly you risk loosing emails, being submerged by spams or being considered as spammer by others and not be able to send emails. That being said, I've been running my own mail server for almost a decade without any major issue.
To get a fully functional web server, you will need to go through these guides:
