mail server on centos 8
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Install Postfix.
# dnf -y install mailx mutt nmap postfix*
postconf -A
postfix check
postconf -v
postconf -h
postconf -n
Run the following command and you will see pcre is now supported.
postconf -m
systemctl enable postfix
systemctl restart postfix
useradd -m -p VCX97jg6iZebc -s /sbin/nologin accesstel
useradd -m -p 4w5yRzfvfQFAI -s /sbin/nologin u1
useradd -m -p 4w5yRzfvfQFAI -s /sbin/nologin u2
useradd -m -p 4w5yRzfvfQFAI -s /sbin/nologin virusalert
useradd -m -p 4w5yRzfvfQFAI -s /sbin/nologin virusmails
useradd -m -p 4w5yRzfvfQFAI -s /sbin/nologin spamalert
useradd -m -p 4w5yRzfvfQFAI -s /sbin/nologin spam.police
useradd -m -p 4w5yRzfvfQFAI -s /sbin/nologin sys_admin
useradd -m -p 4w5yRzfvfQFAI -s /sbin/nologin inmail
useradd -m -p 4w5yRzfvfQFAI -s /sbin/nologin outmail
useradd -m -p 4w5yRzfvfQFAI -s /sbin/nologin junkmail
# cd /etc/postfix
touch body_checks
touch recipient_bcc
touch sender_bcc
touch block_attachments
touch allowed-users
touch restricted-mail-groupsvi
touch local_domains
touch restricted_senders
cp /etc/aliases /etc/postfix/aliases
cp main.cf main.cf.ORG
cp master.cf master.cf.ORG
cp aliases aliases.ORG
cp access access.ORG
cp /etc/postfix/main.cf /etc/postfix/main.cf.ORG
cp /etc/postfix/master.cf /etc/postfix/master.cf.ORG
# vi /etc/postfix/main.cf
135 # inet_interfaces = localhost
138 # inet_protocols = all
183 # mydestination = $myhostname, localhost.$mydomain, localhost
709 # smtpd_tls_cert_file = /etc/pki/tls/certs/postfix.pem
715 # smtpd_tls_key_file = /etc/pki/tls/private/postfix.key
This example shows to configure SMTP-Auth to use Dovecot's SASL function.
[root@mail ~]# vi /etc/postfix/main.cf
# line 95: uncomment and specify hostname
myhostname = mail.worldcm.net
# line 102: uncomment and specify domain name
mydomain = worldcm.net
# line 118: uncomment
myorigin = $mydomain
# line 135: change
inet_interfaces = all
# line 138: change it if use only IPv4
inet_protocols = ipv4
# line 183: add
mydestination = $myhostname, localhost.$mydomain, localhost, $mydomain
# line 283: uncomment and specify your local network
mynetworks = 127.0.0.0/8, 10.0.0.0/24
# line 438: uncomment (use Maildir)
home_mailbox = Maildir/
# line 593: add
smtpd_banner = $myhostname ESMTP
# add follows to the end
# for example, limit an email size for 10M
message_size_limit = 10485760
# for example, limit a mailbox for 1G
mailbox_size_limit = 1073741824
# SMTP-Auth setting
smtpd_sasl_type = dovecot
smtpd_sasl_path = private/auth
smtpd_sasl_auth_enable = yes
smtpd_sasl_security_options = noanonymous
smtpd_sasl_local_domain = $myhostname
smtpd_recipient_restrictions = permit_mynetworks, permit_auth_destination, permit_sasl_authenticated, reject
[root@mail ~]# systemctl enable --now postfix
[3] If Firewalld is running, allow SMTP service. SMTP uses [25/TCP].
[root@mail ~]# firewall-cmd --add-service=smtp --permanent
success
[root@mail ~]# firewall-cmd --reload
success
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