AntiVirus
If you decide to use postfix to receive emails you might also like the free libre open clamd, clamav & clamtk AntiVirus programclamd
install# yum install clamd
which will also install freshclam which you can also run manually on the command line to freshen up your clamav database
clamav
should automatically be installed by above# yum install clamav
clamtk
optional graphical gui for clamav# yum install clamtk

dont forget to
ssh -X yourremotehost
ssh -Y yourremotehost
REFERRERS
PostFix
PostfixDebugging