Hi, any Way to install and configure mail server for internal network using in opnsense?
Tanks.
That's not the function of a firewall and a mail server should be on an internal server on the LAN or DMZ depending on your requirements.
..somefink of a raspi is enough, should work on other Linux anyways...
https://www.raspberrypi.org/forums/viewtopic.php?f=91&t=148337&p=999856#p999856
OpenSMPTD is available as a package, very easy to configure from the command line:
# pkg install opensmtpd