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turn off unwanted services (startup scripts)
Log in as root for all of the following instructions. Type the commands that follow the "#" sign.

# chkconfig --list
this will show what services start up automatically when you boot server and at what run levels the service is off and on. Unlike windows linux has 6 diferent levels that it runs at starting with single user/no network access to full multiuser with network access. The runlevels themselves are not important in this guide, but the server that you are building will most likely always be running at runlevel 3 (full multi user with network and no x-windows running, because you didn't install x-windows).

to turn off individual services
# chkconfig --levels 123456 <servicename> off
this will turn off the service that you named off in run levels 1 - 6
turn off netfs and sendmail

now add postfix
postfix is a replacement for sendmail, if you are thinking about removing the sendmail rpm, do not. Some of the libraries included in the sendmail rpm are used by postfix. Although you need to have sendmail's rpm installed, sendmail and postfix are not compatable with each other. If both are running at the same time, that would be bad. So, to make your change take effect
# chkconfig --add postfix
notice postfix is set to run on levels 2,3,4,5, just like sendmail was.
if it is not already
# chkconfig --levels 2345 postfix on
Now turn off sendmail and turn on postfix.
# /etc/init.d/sendmail stop
# /etc/init.d/postfix start

now tweak the postfix config file
# cd /etc/postfix
edit main.cf to match up to the needs of what you want to do. You need to specify things like the hostname, domain, relay options etc. I would suggest not giving the name and version number of the mailer (postfix) that you are running, as that tells hackers more than they need to know. Read the config file as it explains everything pretty well.

oops, fix my mistake

I realized after testing the mail system that I do not have pine (text based email client) installed. So locate the pine rpm in the redhat 7.3 cd set and install it, or get it from your favorite redhat ftp mirror. To get it via ftp.
# ncftp your favorite.ftp.sitename.here
Then navigate to the RPMS directory with standard unix commands and
# get pine-4.XX-X.i386.rpm
Then exit
# quit
Now install the pine rpm
# rpm -ivh pine-4.XX-X.i386.rpm
To check your email on the local system
# pine
Pine is a very basic text based email program, read the options at the bottom of the screen and check to see what messages the system has sent to the root account already. You will find that all of the cron jobs that you run send an email with the results of the job to the user that the cron job is running under. When we install and test tripwire you will see how this is an important tool.

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