I understand that Exim 4 is the default MTA in Debian. I have a Nagios server installed on Debian, and a mailserver based on Postfix and Courier elsewhere in the network. I want to set up Exim to be able to send mails to that mailserver. The point in the end will be to set up Nagios to forward notifications via mail.
Right now, sendign mail over the network with mailx does not work from the Nagios server.
MX record is set, and mail server can receive mail normally.
Are there any simple how to's or guides to set this up correctly and easily?