If you have not installed sendmail, then install it as follows:

# yum install sendmail

The sendmail directory is /etc/mail.

There are two configuration files:

• sendmail.cf
• submit.cf

sendmail.mc

This is the sendmail macro config file for m4. If you make changes to
/etc/mail/sendmail.mc, you will need to regenerate the
/etc/mail/sendmail.cf file by running the following command:
installed and then performing a
#     make -C /etc/mail

local-host-names file allow you to include all aliases for your machine.

/etc/aliases file allow you to forward email from one user to another user.

To configure sendmail

1. # vi /etc/mail/sendmail.mc

2. Find the following directive(which it limits sendmail to the local computer) :

   DAEMON_OPTIONS(`Port=smtp,Addr=127.0.0.1, Name=MTA')dnl

3. Change it To:

   dnl DAEMON_OPTIONS(`Port=smtp,Addr=127.0.0.1, Name=MTA')dnl

4. Add net works IP addresses to /etc/mail/access, for example, to allow all computers on the 192.168.1.0 net work to send mail to your server, you would do the following:

   # vi /etc/mail/access

5. Iinsert 192.168.1(with out a dot at the end of the IP.)

   192.168.1      RELAY

6. Back up /etc/mail/sendmail.cf
7. Compile the the sendmail.mc program by using this command:

   # make -C /etc/mail

8. Restart sendmail

   # service sendmail restart

9. # chkconfig sendmail on

If you have installed and configured both sendmail and postfix, do not start them at the same time. Only one should be started.For example,

# service sendmail stop
 # service postfix start

To switch between the two electronic mails, use one of the following command:

# system-switch-mail
# alternatives --config mta

To send mail to another user, use the mail command.

1. # mail root

2. Type the message in the Subject field
3. When you are done press CTRL-D
4. Enter another address in the Cc field
5. Press Enter to send the message

# mail root
Subject: This is a test.....
Cc: 
Null message body; hope that's ok
 

To read message 1

# mail

& 1

d command deletes the message

q command quit from the mail program