This document explains how to completely install and configure Postfix for outgoing (SMTP) mail on CentOS 6.
# yum install postfix
# yum install cyrus-sasl
# yum install cyrus-imapd
While you may use whatever editor you choose, this guide assumes you use nano as your editor.
Run the following command to open up the postfix configuration.
# nano /etc/postfix/main.cf
The following code is a shortened version of the default Postfix configuration file. Simply copy it and paste it over the existing configuration. Be sure to replace example.com with your domain name. To save and exit, press Ctrl + O to write out, and Ctrl + X to exit.
soft_bounce = no
queue_directory = /var/spool/postfix
command_directory = /usr/sbin
daemon_directory = /usr/libexec/postfix
mail_owner = postfix
# The default_privs parameter specifies the default rights used by
# the local delivery agent for delivery to external file or command.
# These rights are used in the absence of a recipient user context.
# DO NOT SPECIFY A PRIVILEGED USER OR THE POSTFIX OWNER.
#
#default_privs = nobody
myhostname = mail.example.com
mydomain = example.com
mydestination = $myhostname, localhost
unknown_local_recipient_reject_code = 550
mynetworks_style = host
mailbox_transport = lmtp:unix:/var/lib/imap/socket/lmtp
local_destination_recipient_limit = 300
local_destination_concurrency_limit = 5
recipient_delimiter=+
virtual_alias_maps = hash:/etc/postfix/virtual
header_checks = regexp:/etc/postfix/header_checks
mime_header_checks = pcre:/etc/postfix/body_checks
smtpd_banner = $myhostname
debug_peer_level = 2
debugger_command =
PATH=/bin:/usr/bin:/usr/bin:/usr/X11R6/bin
xxgdb $daemon_directory/$process_name $process_id & sleep 5
sendmail_path = /usr/sbin/sendmail.postfix
newaliases_path = /usr/bin/newaliases.postfix
mailq_path = /usr/bin/mailq.postfix
setgid_group = postdrop
html_directory = no
manpage_directory = /usr/share/man
sample_directory = /usr/share/doc/postfix-2.3.3/samples
readme_directory = /usr/share/doc/postfix-2.3.3/README_FILES
smtpd_sasl_auth_enable = yes
smtpd_sasl_application_name = smtpd
smtpd_recipient_restrictions = permit_sasl_authenticated,
permit_mynetworks,
reject_unauth_destination,
reject_invalid_hostname,
reject_non_fqdn_hostname,
reject_non_fqdn_sender,
reject_non_fqdn_recipient,
reject_unknown_sender_domain,
reject_unknown_recipient_domain,
reject_unauth_pipelining,
reject_rbl_client zen.spamhaus.org,
reject_rbl_client bl.spamcop.net,
reject_rbl_client dnsbl.njabl.org,
reject_rbl_client dnsbl.sorbs.net,
permit
smtpd_sasl_security_options = noanonymous
smtpd_sasl_local_domain =
broken_sasl_auth_clients = yes
smtpd_helo_required = yes