SEND MAIL SERVER

MTA:-> Mail transport agentProtocol used in mail server.
SMTP:- Simple mail transfer protocol..which work on 25 port number. Used for sending the mail.
Incoming mail :-- user have mail account on mail server, then user connect to via a mail server using a MUA i.e mail user agent like outlook,evolution and command line tool like mutt.
protocol used for pop 110 (popst office protocol) or imap 143 (internet mail access protocol).

Installing Sendmail.
packages are required sendmail-cf, sendmail
#service sendmail restart
configuration file for sendmail.
/etc/mail/sendmail.cf original conf file but very hard to configure understand.
/etc/mail/sendmail.mc This is macro file which is used to configure mail server.

edit this file... vi sendmail.mc
DAEMON_OPTIONS(`Port=smtp,Addr=127.0.0.1, Name=MTA') dnl
DAEMON_OPTIONS(`Port=smtp,Addr=ur server ip, Name=MTA') dnl
save the file and run this command
m4 /etc/mail/sendmail.mc > /etc/mail/sendmail.cf

#Service sendmail retstart
#pgrep sendmail
#netstat -an grep : 25

For test sendmail working or not
#telnet ur server ip 25
quit

#/etc/mail/access :- This file control for which network can use this mail server as an outgoing mail server.This file has two coloume
1st for ip or hostname and 2nd used for action in which keyboard like RELAY,OK,REJECT,DISCARD
#/etc/mail/localhostname
raman.net.in
whenever you change in anyfile run this cmd #make
#/etc/aliases :-- used for redirect your mail. two field
1 for actual user: 2 for which user
To activate the changes run this command #newaliases
Install Dovecot for pop or imap
#/etc/dovecot.conf
protocol = imap imaps pop3 pop3s
service dovecot restart