Setup mail server on centos 7<\/p>\n
This article helps you to install and configure basic mail server on Centos 7. Here i have used Postfix for SMTP, Dovecot for POP\/IMAP and Dovecot SASL for SMTP AUTH.
\nBefore proceeding please make sure you have assigned static IP for the server and have internet connectivity for installing packages.<\/p>\n
Setup mail server on centos 7
\n1. Installing packages
\n2. Postfix configuration
\n3. Dovecot configuration
\n4. User creation<\/p>\n
Installing packages
\nStep 1 \u00bb Assign hostname for the server using the below command.
\n[root@rmohan ~]# hostnamectl set-hostname mail.rmohan.com<\/p>\n
Step 2 \u00bb Make a host entry with your IP in \/etc\/hosts file.
\n192.168.1.20 mail.rmohan.com<\/p>\n
Step 3 \u00bb Now start installing packages.
\n[root@rmohan ~]# yum -y install postfix dovecot<\/p>\n
After package installation continue with postfix configuration.<\/p>\n
Postfix configuration
\nFirst create SSL certificate for encryption.
\nStep 4 \u00bb Follow the below steps one by one for creation.
\n[root@mail ~]# mkdir \/etc\/postfix\/ssl
\n[root@mail ~]# cd \/etc\/postfix\/ssl
\n[root@rmohan ssl]# openssl genrsa -des3 -out server.key 2048
\n[root@rmohan ssl]# openssl rsa -in server.key -out server.key.insecure
\n[root@rmohan ssl]# mv server.key server.key.secure
\n[root@rmohan ssl]# mv server.key.insecure server.key
\nLeave blank for A challenge password [] value in the below step.
\n[root@rmohan ssl]# openssl req -new -key server.key -out server.csr
\n[root@rmohan ssl]# openssl x509 -req -days 365 -in server.csr -signkey server.key -out server.crt<\/p>\n
Step 5 \u00bb Now open \/etc\/postfix\/main.cf file for changes.
\nFind and uncomment the below lines.
\n#inet_interfaces = localhost #—> line no 116
\n#mydestination = $myhostname, localhost.$mydomain, localhost #–> line no 164<\/p>\n
and add below lines at the end of the file. change myhostname and mydomain values with yours and home_mailbox value to your desired directory. Here it will store mails in the users home directory (Eg: \/home\/rmohan\/mail ).<\/p>\n
myhostname = mail.rmohan.com
\nmydomain = rmohan.com
\nmyorigin = $mydomain
\nhome_mailbox = mail\/
\nmynetworks = 127.0.0.0\/8
\ninet_interfaces = all
\nmydestination = $myhostname, localhost.$mydomain, localhost, $mydomain
\nsmtpd_sasl_type = dovecot
\nsmtpd_sasl_path = private\/auth
\nsmtpd_sasl_local_domain =
\nsmtpd_sasl_security_options = noanonymous
\nbroken_sasl_auth_clients = yes
\nsmtpd_sasl_auth_enable = yes
\nsmtpd_recipient_restrictions = permit_sasl_authenticated,permit_mynetworks,reject_unauth_destination
\nsmtp_tls_security_level = may
\nsmtpd_tls_security_level = may
\nsmtp_tls_note_starttls_offer = yes
\nsmtpd_tls_loglevel = 1
\nsmtpd_tls_key_file = \/etc\/postfix\/ssl\/server.key
\nsmtpd_tls_cert_file = \/etc\/postfix\/ssl\/server.crt
\nsmtpd_tls_received_header = yes
\nsmtpd_tls_session_cache_timeout = 3600s
\ntls_random_source = dev:\/dev\/urandom<\/p>\n
Step 6 \u00bb Open \/etc\/postfix\/master.cf file, add the below lines after \u201csmtp inet n \u2013 n \u2013 \u2013 smtpd\u201d line.
\nsubmission\u00a0\u00a0\u00a0\u00a0 inet\u00a0 n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 –\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 –\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 –\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 smtpd
\n-o syslog_name=postfix\/submission
\n-o smtpd_sasl_auth_enable=yes
\n-o smtpd_recipient_restrictions=permit_sasl_authenticated,reject
\n-o milter_macro_daemon_name=ORIGINATING
\nsmtps\u00a0\u00a0\u00a0\u00a0 inet\u00a0 n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 –\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 –\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 –\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 smtpd
\n-o syslog_name=postfix\/smtps
\n-o smtpd_sasl_auth_enable=yes
\n-o smtpd_recipient_restrictions=permit_sasl_authenticated,reject
\n-o milter_macro_daemon_name=ORIGINATING
\nNow check the configuration using postfix check command.
\nStep 7 \u00bb Now configure Dovecot SASL for SMTP Auth. Open \/etc\/dovecot\/conf.d\/10-master.conf file, find \u201c# Postfix smtp-auth\u201d line ( line no:95 ) and add the below lines.
\n# Postfix smtp-auth
\nunix_listener \/var\/spool\/postfix\/private\/auth {
\nmode = 0660
\nuser = postfix
\ngroup = postfix
\n}<\/p>\n
Step 8 \u00bb Open \/etc\/dovecot\/conf.d\/10-auth.conf file, find \u201cauth_mechanisms = plain\u201d ( Line no: 100 ) and add login to the value like below.
\nauth_mechanisms = plain login<\/p>\n
Step 9 \u00bb Postfix configuration is over. Now restart both postfix and dovecot services and enable auto start.
\n[root@mail ~]# systemctl restart postfix
\n[root@mail ~]# systemctl enable postfix
\n[root@mail ~]# systemctl restart dovecot
\n[root@mail ~]# systemctl enable dovecot<\/p>\n
Step 10 \u00bb Add the firewall rules to allow 25, 587 and 465 ports.
\n[root@mail ~]# firewall-cmd –permanent –add-service=smtp
\n[root@mail ~]# firewall-cmd –permanent –add-port=587\/tcp
\n[root@mail ~]# firewall-cmd –permanent –add-port=465\/tcp
\n[root@mail ~]# firewall-cmd –reload
\nNow start testing connectivity for each ports 25,587 and 465 using telnet and make sure you are getting AUTH PLAIN LOGIN line after issuing ehlo mail.rmohan.com command in telnet.
\n[root@mail ~]# telnet mail.rmohan.com 465
\nTrying 192.168.1.20…
\nConnected to mail.rmohan.com.
\nEscape character is ‘^]’.
\n220 mail.rmohan.com ESMTP Postfix
\nehlo mail.rmohan.com <——- Type this command
\n250-mail.rmohan.com
\n250-PIPELINING
\n250-SIZE 10240000
\n250-VRFY
\n250-ETRN
\n250-STARTTLS
\n250-AUTH PLAIN LOGIN
\n250-AUTH=PLAIN LOGIN
\n250-ENHANCEDSTATUSCODES
\n250-8BITMIME
\n250 DSN<\/p>\n
Dovecot configuration
\nStart configuring Dovecot .
\nStep 11 \u00bb Open \/etc\/dovecot\/conf.d\/10-mail.conf file, find #mail_location = (line no : 30 ) and add the same directory which is given to home_mailbox in the postfix config file ( Step 5).
\nmail_location = maildir:~\/mail<\/p>\n
Step 12 \u00bb Open \/etc\/dovecot\/conf.d\/20-pop3.conf file, find and uncomment the below line ( line no : 50 ) .
\npop3_uidl_format = %08Xu%08Xv<\/p>\n
Step 13 \u00bb Restart dovecot service.
\n[root@mail ~]# systemctl restart dovecot<\/p>\n
Step 14 \u00bb Add firewall rules to allow 110,143,993 and 995.
\n[root@mail ~]# firewall-cmd –permanent –add-port=110\/tcp
\n[root@mail ~]# firewall-cmd –permanent –add-service=pop3s
\n[root@mail ~]# firewall-cmd –permanent –add-port=143\/tcp
\n[root@mail ~]# firewall-cmd –permanent –add-service=imaps
\n[root@mail ~]# firewall-cmd –reload<\/p>\n
Check the connectivity for the ports 110,143,993 and 995 using telnet.<\/p>\n
User creation
\nNow create user for testing .
\nStep 15 \u00bb Create user with \/sbin\/nologin shell to restrict login access.
\n[root@mail ~]# useradd -m rmohan -s \/sbin\/nologin
\n[root@mail ~]# passwd rmohan<\/p>\n","protected":false},"excerpt":{"rendered":"
Setup mail server on centos 7<\/p>\n
This article helps you to install and configure basic mail server on Centos 7. Here i have used Postfix for SMTP, Dovecot for POP\/IMAP and Dovecot SASL for SMTP AUTH. Before proceeding please make sure you have assigned static IP for the server and have internet connectivity for installing […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[73],"tags":[],"_links":{"self":[{"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/posts\/4534"}],"collection":[{"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/mohan.sg\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=4534"}],"version-history":[{"count":1,"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/posts\/4534\/revisions"}],"predecessor-version":[{"id":4535,"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/posts\/4534\/revisions\/4535"}],"wp:attachment":[{"href":"https:\/\/mohan.sg\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=4534"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mohan.sg\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=4534"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mohan.sg\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=4534"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}