Configuring the local mail system

Without mail redirection, mail destined for the root is delivered to root@fi.muni.cz (and in general mail for login users arrives at login@fi.muni.cz). To redirect, you need to create an alias and properly configure a mail system that supports aliases (e.g. Postfix, Exim).

Mail system configuration (Postfix)

Install the package postfix. In the case of installation queries (Debian/Ubuntu/...), select Internet with smarthost, enter the FQDN of your machine as smarthost [relay.fi.muni.cz] (including brackets) and you can leave the other entries default. Alternatively, you can then edit the Postfix configuration manually:

# vi /etc/postfix/main.cf

and add the line

relayhost = [relay.fi.muni.cz]

and then run the command

# postfix reload

Secure Postfix startup on system boot:

# systemctl enable postfix

Redirect Mail

The aliases are stored in the file /etc/aliases (or /etc/mail/aliases):

# vi /etc/aliases

To redirect mail for the user root, add the line

root: login@fi.muni.cz

Redirect mail for your regular account in the same way. Apply the change and update the alias database

# newaliases

For more information about aliases, see man 5 aliases.

Setting the hostname

Make sure you have the correct hostname set up, including the domain:

$ hostname
yourfimachine.fi.muni.cz

Typically, you can set the hostname with the command

# hostnamectl set-hostname yourfimachine.fi.muni.cz

Functionality test

Install the command mail (not included with Postfix). It is provided by the mailutils or s-nail package. It is generally useful: some other services (e.g. [SMART daemon](installation.html#smart) rely on it.

Then verify that the test mail arrives in your faculty mailbox (for both root and your local login), e.g.:

$ echo A very short body | mail root -s Subject
$

Redirecting mail generated by the command sudo

To redirect mail of the form *** SECURITY information for XY.fi.muni.cz ***to a non-implicit address, add the line visudo to the new file /etc/sudoers.d/mailto

Defaults mailto = login@fi.muni.cz

However, verify that /etc/sudoers contains the line #includedir /etc/sudoers.d. Alternatively, edit /etc/sudoers directly.

Redirecting mail from cron

To redirect mail from cron, you need to add a line to the file from which the tasks are run before the task definitions

MAILTO=login@fi.muni.cz

Troubleshooting

If you run into problems during configuration, the mail system logs, usually located at /var/log/mail*, /var/log/postfix or /var/log/exim*/, can be useful. To find out the contents of the local mail queue, use the command mailq. If you don't know what to do, will help you.