As part of a restructure at home I wanted to setup my router to be able to send email for all the servers on my LAN.
I tested it using Fastmail, but I know this will also work with Gmail. (I used the same setup when I had a gmail-account)
I did it like so:
:~# apt-get install exim4
:~# dpkg-reconfigure exim4-config
“Mail sent by smarthost; no local mail”
“System mail name: Home.Local”
IP-Address to listen on: Type in the LAN-IP of your router, or 0.0.0.0 if it’s entirely on a private/trusted LAN. (for example a standalone raspberry PI.)
“Other destinations for which mail is accepted: <leave blank>”
“Visible Domain name for local users: Home.Local”
IP-address or host name of the outgoing smarthost: This one depends on YOUR smarthost. Fastmail uses “mail.messagingengine.com::587”.
If you are lucky, you will get a prompt for, “Domains to relay mail for:” here, if that’s the case – Enter “*” and continue, otherwise we have to do something more.
Number-of-DNS-queries minimal, No.
Split configuration into small files, No.
If you were lucky, skip to configuring passwd.client, otherwise:
:~# editor /etc/exim4/update-exim4.conf.con
Fint and edit dc_relay_domains=” and add a *, so that it reads “dc_relay_domains=’*'”.
(Don’t just copy/paste that, quotes etc.)
Save the file, and re-run config to verify, then go ahead.
:~# editor /etc/exim4/passwd.client
And input using the following variables:
<servername>:<username>:<password>
For fastmail this equalls:
mail.messagingengine.com:leetuser@fastmail.com:leethax0rpassword
Save and restart exim using:
:~# systemctl restart exim4.service
Send a test-mail using:
:~# echo “testmail!” | mailx testmail@example.com
It should arrive!
Now for the clients in your LAN, the following should be done:
:~# apt-get install exim4
:~# dpkg-reconfigure exim4-config
“Mail sent by smarthost; no local mail”
“System mail name:” Leave as-is, should contain hostname+domain.
“IP-addresses to listen on for incoming SMTP connections:” Leave to something loopback-ish. (127.0.0.1, ::1)
“Other destinations for which mail is accepted:” Leave as-is.
“Visible domain name for local users:” Leave as-is.
“IP address or host name of the outgoing smarthost:” Enter the hostname/IP of the host created during the first part.
Number-of-DNS-queries minimal, No.
Split configuration into small files, No.
And then send a test-mail using the following command:
:~# echo “Testing mail via relay at <clock>” | mailx receiver@example.com
It can also be a good idea to update the mail-alias on the client.
:~# editor /etc/aliases
Replace the entry after root with a valid (and monitored) email, for example:
root: user+fileserver@example.com
Save the file, and you’re done.
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