What is Exim?

Exim is an open source mail transfer agent (MTA), which is a program responsible for receiving, routing, and delivering e-mail messages (this type of program is sometimes referred to as an Internet mailer, or a mail server program).

How to install Exim

Install exim and mail switching tools

# yum install exim*

# yum install system-switch-mail*

Switch your MTA & set exim to start on boot

system-switch-mail

service sendmail stop

service exim start

chkconfig exim on

chkconfig sendmail off

Add a root alias, eg: “root: me@example.com”

# vi /etc/aliases

You may also wish to add some config to your routers section like this, if you want to relay through a smart host.

# vi /etc/exim/exim.conf

Then add this before the “dnslookup:” section.

to_smart_host:
driver = manualroute
domains = ! +local_domains
transport = remote_smtp
route_list = “* mail1.example.com:mail2.example.com;”
Restart exim
service exim restart
To test, send an email
echo “test” |mail -s “$HOSTNAME” me@example.com
Then you can flush the Exim Que and watch the log like this
exim -qff ; tail -f /var/log/exim/main.log
Name of Config File
# exim.conf
Usual Location of Config Directory
# /etc/exim
Usual Permissions required on Exim Binaries
owner:root, group:root, permissions:755
Usual Permissions required on Config Files
owner:exim, group:exim, permissions:644
Usual Spool Directory
/var/spool/exim
Usual Queue Directory
/var/spool/exim/input
Usual Logfile Directory
/var/log/exim
Good luck!