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Mail Server
I need a simple, lightweight mail server to gather together system reports and alerts. This will not be exposed to the Internet. It will neither be able to send or receive messages from the outside world.
Preparing the Mail Server Jail
1. Log in to your TrueNAS server as root using SSH or the Shell option of the TrueNAS Web Portal.
2. Make some decisions and define some variables.
# Tailor each of these examples for your own situation JAIL_NAME="net" # name of the jail that will contain the mail server
Set up the Mail Delivery Agent
I will be using the simple sendmail service that comes as standard with BSD installations. It just needs to be configured and started. I don't need any clever security, as it can only be accessed from the LAN, and I'm not going to tell it how to pass messages on to the outside world.
1. Build the initial configuration
jexec "ioc-${JAIL_NAME:?}" /bin/sh -c "cd /etc/mail && make"
2. Define the default mailbox where all system messages are sent.
jexec "ioc-${JAIL_NAME:?}" /bin/sh "cd /etc/mail && make"
jexec "ioc-${JAIL_NAME:?}" sysrc sendmail_enable="NO"
jexec "ioc-${JAIL_NAME:?}" sysrc sendmail_outbound_enable="NO"
jexec "ioc-${JAIL_NAME:?}" sysrc sendmail_submit_enable="YES"
jexec "ioc-${JAIL_NAME:?}" sysrc sendmail_msp_queue_enable="YES"
jexec "ioc-${JAIL_NAME:?}" service sendmail restart
Set up the POP Mailbox Service
I need to be able to view messages on my workstation using a normal mail reader. The messages I receive will be actioned and then deleted. I don't need the clever folders that IMAP provides, so I'll just use the POP protocol to access the mailbox.
Initially I just want one mailbox for all notifications from the various devices across my LAN. This can easily be configured by creating a normal Unix user on the mail server box. They don't need to be able to log in, but the normal passwd and shadow files will store all the configuration we need for each mailbox. The root login and other system logins will be set to forward their mail to my special email address on the same host.
Set up Thunderbird to access the Mailbox
Credits
This page has been cobbled together from various bits of information I've found on the Internet.