CentOS 5
Install/Configure Postfix
  This is How to Build SMTP Server with Postfix.

[1] Install/Configure Postfix
[root@mail ~]#
yum -y install postfix


[root@mail ~]#
vi /etc/postfix/main.cf


# line 70: uncomment and specify hostname

myhostname =
mail.server.world


# line 77: uncomment and specify domain name

mydomain =
server.world


# line 93: uncomment

myorigin = $mydomain

# line 110: change

inet_interfaces =
all


# line 155: add

mydestination = $myhostname, localhost.$mydomain, localhost
, $mydomain


# line 255: uncomment and specify LAN

mynetworks = 127.0.0.0/8,
10.0.0.0/24


# line 410: uncomment (use Maildir)

home_mailbox = Maildir/

# line 536: uncomment; line 537: add

header_checks = regexp:/etc/postfix/header_checks
body_checks = regexp:/etc/postfix/body_checks


# line 562: add

smtpd_banner = $myhostname ESMTP


# add at the bottom

# limit an email size 5M

message_size_limit = 5242880

# limit mailbox 100M

mailbox_size_limit = 104857600


# for SMTP-Auth setting

smtpd_sasl_type = dovecot
smtpd_sasl_path = private/auth-client
smtpd_sasl_auth_enable = yes
smtpd_sasl_security_options = noanonymous
smtpd_sasl_local_domain = $myhostname
smtpd_client_restrictions = permit_mynetworks,reject_unknown_client,permit
smtpd_recipient_restrictions = permit_mynetworks,permit_auth_destination,permit_sasl_authenticated,reject


[root@mail ~]#
vi /etc/postfix/header_checks


# add at the head

# reject if email address is empty

/^From:.*<#.*@.*>/ REJECT
/^Return-Path:.*<#.*@.*>/ REJECT
# hide Received line

/^Received:/ IGNORE


[root@mail ~]#
vi /etc/postfix/body_checks


# reject if includes 'example.com' in mail body

/^(|[^>].*)example.com/ REJECT


[root@mail ~]#
/etc/rc.d/init.d/sendmail stop

Shutting down sm-client:
[  OK  ]

Shutting down sendmail:
[  OK  ]

[root@mail ~]#
chkconfig sendmail off

[root@mail ~]#
alternatives --config mta
 
# change default MTA


There are 2 programs which provide 'mta'.

Selection      Command
-----------------------------------------------
*+ 1
  /usr/sbin/sendmail.sendmail

2
  /usr/sbin/sendmail.postfix


Enter to keep the current selection[+], or type selection number:
2
 
# switch to postfix


[root@mail ~]#
/etc/rc.d/init.d/postfix start

Starting postfix:
[  OK  ]

[root@mail ~]#
chkconfig postfix on