Thought of sharing this with you all 
Allowing exim to run automatically on ports other than 25 and 26
We can achieve this by starting exim on the particular port (say 588) using the following command:
/usr/sbin/exim -oX 588 -bd
But to get this done automatically whenever exim starts, do the following:
1) In /etc/chkserv.d, add a file called exim_588 (to run it on port 588).
Note the underscore there. Do not replace it with hyphen as there is another file exim-26 that uses that. The content of the file would be:
service[exim-588]=588,QUIT,220,/etc/rc.d/init.d/exim stop;/etc/rc.d/init.d/exim stop;/etc/rc.d/init.d/exim stop;/etc/rc.d/init.d/exim start;/usr/sbin/exim -oX 588 -bd
2) Enable it in /etc/chkserv.d/chkservd.conf
exim_588:1
3) Now make the following changes in /etc/init.d/exim. Search for ALTPORT and add the following lines below that:
if [ "`echo $file | awk -F_ '{ print $1 }'`" = "exim" ]; then
ALTPORT2=”`echo $file | awk -F_ ‘{ print $2 }’`”
fi
Again search for it and add these lines:
if [ "$ALTPORT2" != "" -a "`grep \"daemon_smtp_port.* $ALTPORT2\" /etc/exim.conf`" = "" ]; then
echo -n “Starting exim-$ALTPORT2: ”
TMPDIR=/tmp $DAEMONIZE /usr/sbin/exim -bd -oX $ALTPORT2
echo $RESULT
fi
This will ensure that exim runs on port 588 on start. You can also see it enabled in Whm >> Service Manager.
Allowing exim to run automatically on ports other than 25 and 26
We can achieve this by starting exim on the particular port (say 588) using the following command:
/usr/sbin/exim -oX 588 -bd
But to get this done automatically whenever exim starts, do the following:
1) In /etc/chkserv.d, add a file called exim_588 (to run it on port 588).
Note the underscore there. Do not replace it with hyphen as there is another file exim-26 that uses that. The content of the file would be:
service[exim-588]=588,QUIT,220,/etc/rc.d/init.d/exim stop;/etc/rc.d/init.d/exim stop;/etc/rc.d/init.d/exim stop;/etc/rc.d/init.d/exim start;/usr/sbin/exim -oX 588 -bd
2) Enable it in /etc/chkserv.d/chkservd.conf
exim_588:1
3) Now make the following changes in /etc/init.d/exim. Search for ALTPORT and add the following lines below that:
if [ "`echo $file | awk -F_ '{ print $1 }'`" = "exim" ]; then
ALTPORT2=”`echo $file | awk -F_ ‘{ print $2 }’`”
fi
Again search for it and add these lines:
if [ "$ALTPORT2" != "" -a "`grep \"daemon_smtp_port.* $ALTPORT2\" /etc/exim.conf`" = "" ]; then
echo -n “Starting exim-$ALTPORT2: ”
TMPDIR=/tmp $DAEMONIZE /usr/sbin/exim -bd -oX $ALTPORT2
echo $RESULT
fi
This will ensure that exim runs on port 588 on start. You can also see it enabled in Whm >> Service Manager.