this is rhel ? and not cent ?
for redhat you HAVE to buy the required support contract and register your install
then you can install software
the standard one year single DESKTOP contract is $299 / year (USD)
-- server license is $799 per year
also unless you are using this redhat server as a mail server or a AD server
mcafee will really ONLY look for Microsoft Windows viruses in attachments and in incoming and out going mail and files
redhat can not run the MICROSOFT viruses and as such can not be infected BY the Microsoft Windows viruses
linux is already immune to the MS Windows viruses
but
if you get a lot of files from windows users you CAN ( like typhoid Marry) spread them to OTHER windows users
this is where the FREE ClamAV comes in
and will be in the RHN repo that you have access to with your paid for support contract
Code:
su -
yum install clamav