Hack The Sec-Leading Resource Of Linux Tutorial: Linux-Mail-Server

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<span style="color: #990000; font-family: Trebuchet, Trebuchet MS, Arial, Verdana, sans-serif; font-size: large;"><span style="line-height: 30px;"><u>Setup mail server on centos 7</u></span></span></h1>
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<span style="color: #222222; font-size: 16px; line-height: 30px;">This article helps you to install and configure basic mail server on </span><a href="http://www.hackthesec.co.in/search/label/Centos" style="color: #0f4884; font-size: 16px; line-height: 30px; text-decoration: none;" title="Centos">Centos</a><span style="color: #222222; font-size: 16px; line-height: 30px;"> 7. Here i have used Postfix for SMTP, Dovecot for POP/IMAP and Dovecot SASL for SMTP AUTH.</span></h1>
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<span style="color: #222222; font-family: trebuchet, 'trebuchet ms', arial, verdana, sans-serif; font-size: 16px; line-height: 30px;">Before proceeding please make sure you have assigned static IP for the server and have internet connectivity for installing packages.</span></div>
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                                <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiwXFjlAbKP-BbS_imp_3im9swmB_1h-YvwnJ9adp3dLHRZ8SnhttbxG5pHeSzoLgYS1-xSDzZRkhdzDCgkfeg1k4YK4AC19sZy8_R90QH-NNjOMo2IOvktIgpRdZ1fbp2Ti2SOaCOvx5mV/s1600/mailserver-with-virtual-users-and-domains-using-postfix-and-dovecot-in-centos-6+_www.hackthesec.co.in.png" imageanchor="1"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiwXFjlAbKP-BbS_imp_3im9swmB_1h-YvwnJ9adp3dLHRZ8SnhttbxG5pHeSzoLgYS1-xSDzZRkhdzDCgkfeg1k4YK4AC19sZy8_R90QH-NNjOMo2IOvktIgpRdZ1fbp2Ti2SOaCOvx5mV/s1600/mailserver-with-virtual-users-and-domains-using-postfix-and-dovecot-in-centos-6+_www.hackthesec.co.in.png" /></a></div>
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<span style="color: #0b5394; font-family: trebuchet, trebuchet ms, arial, verdana, sans-serif; font-size: large;"><span style="line-height: 30px;"><b><u>Setup mail server on centos 7</u></b></span></span></div>
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<span style="color: #222222; font-family: Georgia, Times New Roman, serif; font-size: large;"><span style="line-height: 30px;">1. Installing packages</span></span></div>
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<span style="color: #222222; font-family: trebuchet, trebuchet ms, arial, verdana, sans-serif; font-size: large;"><span style="line-height: 30px;">2. Postfix configuration</span></span></div>
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<span style="color: #222222; font-family: trebuchet, trebuchet ms, arial, verdana, sans-serif; font-size: large;"><span style="line-height: 30px;">3. Dovecot configuration</span></span></div>
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<span style="color: #222222; font-family: trebuchet, trebuchet ms, arial, verdana, sans-serif; font-size: large;"><span style="line-height: 30px;">4. User creation</span></span></div>
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<b><u><span style="color: #0b5394; font-size: large;">Step 1: Installing packages</span></u></b></div>
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<span style="color: #222222; font-family: Verdana, Geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">Step 1 : Assign hostname for the server using the below command</span></span><span style="color: #222222; font-family: Verdana, Geneva, sans-serif; font-size: 15px; line-height: 26px;">.</span></div>
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<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-family: Trebuchet MS, sans-serif; font-size: medium;"><span style="line-height: 15.6px;">[root@hackthesec~]# hostnamectl set-hostname mail.hackthesec.co.in</span></span><span style="color: #222222; font-family: trebuchet, trebuchet ms, arial, verdana, sans-serif;"><span style="line-height: 30px; white-space: normal;">
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<span style="font-family: Verdana, Geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;"><span style="color: #222222;">Step 2 : Make a host entry with your IP in </span><span style="color: #990000;"><b>/etc/hosts</b> </span><span style="color: #222222;">file.</span></span></span></div>
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<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-family: Trebuchet MS, sans-serif; font-size: medium;"><span style="line-height: 15.6px;">172.27.0.51 mail.hackthesec.co.in</span></span></pre>
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<span style="color: #222222; font-family: Verdana, Geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">Step 3 : Now start installing packages.</span></span></div>
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<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="font-family: Trebuchet MS, sans-serif; font-size: medium;"><span style="line-height: 15.6px;"><span style="color: white;">[root@hackthesec~]# yum -y </span><span style="color: lime;">install postfix dovecot</span></span></span></pre>
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<span style="color: #222222; font-family: Verdana, Geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">After package installation continue with postfix configuration.</span></span></div>
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<span style="color: #0b5394; font-family: trebuchet, trebuchet ms, arial, verdana, sans-serif; font-size: large;"><span style="line-height: 30px;"><b><u>Step 2 : Postfix configuration</u></b></span></span></div>
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<span style="color: #222222; font-family: Verdana, Geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">First create SSL certificate for encryption.</span></span></div>
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<span style="color: #222222; font-family: Verdana, Geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">Step 4: Follow the below steps one by one for creation</span></span><span style="color: #222222; font-family: Verdana, Geneva, sans-serif; font-size: 15px; line-height: 26px;">.</span></div>
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<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-family: Trebuchet MS, sans-serif; font-size: medium;"><span style="line-height: 15.6px;">[root@hackthesec ~]# mkdir /etc/postfix/ssl
[root@</span></span><span style="color: white; font-family: 'Trebuchet MS', sans-serif; font-size: medium; line-height: 15.6px;">hackthesec</span><span style="color: white; font-family: 'Trebuchet MS', sans-serif; font-size: medium; line-height: 15.6px;"> ~]# cd /etc/postfix/ssl</span>
<span style="color: white; font-family: Trebuchet MS, sans-serif; font-size: medium;"><span style="line-height: 15.6px;">[root@</span></span><span style="color: white; font-family: 'Trebuchet MS', sans-serif; font-size: medium; line-height: 15.6px;">hackthesec</span><span style="color: white; font-family: 'Trebuchet MS', sans-serif; font-size: medium; line-height: 15.6px;"> ssl]# openssl genrsa -des3 -out server.key 2048</span>
<span style="color: white; font-family: Trebuchet MS, sans-serif; font-size: medium;"><span style="line-height: 15.6px;">[root@</span></span><span style="color: white; font-family: 'Trebuchet MS', sans-serif; font-size: medium; line-height: 15.6px;">hackthesec</span><span style="color: white; font-family: 'Trebuchet MS', sans-serif; font-size: medium; line-height: 15.6px;"> ssl]# openssl rsa -in server.key -out server.key.insecure</span>
<span style="color: white; font-family: Trebuchet MS, sans-serif; font-size: medium;"><span style="line-height: 15.6px;">[root@</span></span><span style="color: white; font-family: 'Trebuchet MS', sans-serif; font-size: medium; line-height: 15.6px;">hackthesec</span><span style="color: white; font-family: 'Trebuchet MS', sans-serif; font-size: medium; line-height: 15.6px;"> ssl]# mv server.key server.key.secure</span>
<span style="color: white; font-family: Trebuchet MS, sans-serif; font-size: medium;"><span style="line-height: 15.6px;">[root@</span></span><span style="color: white; font-family: 'Trebuchet MS', sans-serif; font-size: medium; line-height: 15.6px;">hackthesec</span><span style="color: white; font-family: 'Trebuchet MS', sans-serif; font-size: medium; line-height: 15.6px;"> ssl]# mv server.key.insecure server.key</span></pre>
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<span style="font-family: Verdana, Geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;"><span style="color: #222222;">Leave blank for </span><b><span style="color: #990000;">A challenge password []</span></b><span style="color: #222222;"> value in the below step.</span></span></span></div>
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<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="font-family: Trebuchet MS, sans-serif; font-size: medium;"><span style="line-height: 15.6px;"><span style="color: white;">[root@hackthesec ssl]# openssl req -new -key </span><span style="color: lime;">server.key -out server.csr</span><span style="color: white;">
[root@hackthesec ssl]# openssl x509 -req -days 365 -in server.csr -signkey server.key -out server.crt</span></span></span></pre>
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<span style="font-family: Verdana, Geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;"><span style="color: #222222;">Step 5 : Now open</span><span style="color: #990000;"><b> /etc/postfix/main.cf</b></span><span style="color: #222222;"> file for changes.</span></span></span></div>
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<span style="color: #222222; font-family: Verdana, Geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">Find and uncomment the below lines</span></span><span style="color: #222222; font-family: Verdana, Geneva, sans-serif; font-size: 15px; line-height: 26px;">.</span></div>
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<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-family: Trebuchet MS, sans-serif; font-size: medium;"><span style="line-height: 15.6px;">#inet_interfaces = localhost #---> line no 116
#mydestination = $myhostname, localhost.$mydomain, localhost #--> line no 164</span></span></pre>
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<span style="color: #222222; font-family: Verdana, Geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">and add below lines at the end of the file. change <b>myhostname </b>and <b>mydomain </b>values with yours and <b>home_mailbox</b> value to your desired directory. Here it will store mails in the users home directory (Eg: /home/john/mail ).</span></span></div>
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<pre class="xtypo_info" style="background: url("assets/shadow.png") 50% 100% repeat-x rgb(245, 245, 245); border-radius: 4px; border: 1px solid rgb(204, 204, 204); box-shadow: rgb(204, 204, 204) 0px 0px 3px; box-sizing: border-box; color: #333333; font-family: Menlo, Monaco, Consolas, 'Courier New', monospace; font-size: 13px; font-stretch: normal; line-height: 1.42857; margin-bottom: 10px; overflow: auto; padding: 9.5px; tab-size: 4; text-shadow: rgb(255, 255, 255) 0px 1px 0px; white-space: pre-wrap; word-break: break-all; word-wrap: break-word;">myhostname = mail.hackthesec.co.in
mydomain = hackthesec.co.in
myorigin = $mydomain
home_mailbox = mail/
mynetworks = 127.0.0.0/8
inet_interfaces = all
mydestination = $myhostname, localhost.$mydomain, localhost, $mydomain
smtpd_sasl_type = dovecot
smtpd_sasl_path = private/auth
smtpd_sasl_local_domain =
smtpd_sasl_security_options = noanonymous
broken_sasl_auth_clients = yes
smtpd_sasl_auth_enable = yes
smtpd_recipient_restrictions = permit_sasl_authenticated,permit_mynetworks,reject_unauth_destination
smtp_tls_security_level = may
smtpd_tls_security_level = may
smtp_tls_note_starttls_offer = yes
smtpd_tls_loglevel = 1
smtpd_tls_key_file = /etc/postfix/ssl/server.key
smtpd_tls_cert_file = /etc/postfix/ssl/server.crt
smtpd_tls_received_header = yes
smtpd_tls_session_cache_timeout = 3600s
tls_random_source = dev:/dev/urandom</pre>
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<span style="font-family: Verdana, Geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;"><span style="color: #222222;">Step 6 : Open </span><b><span style="color: #990000;">/etc/postfix/master.cf</span></b><span style="color: #222222;"> file, add the below lines after "</span><span style="color: #990000;">smtp inet n – n – – smtpd</span><span style="color: #222222;">" line</span></span></span><span style="color: #222222; font-family: Verdana, Geneva, sans-serif; font-size: 15px; line-height: 26px;">.</span></div>
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<pre class="xtypo_info" style="background: url("assets/shadow.png") 50% 100% repeat-x rgb(245, 245, 245); border-radius: 4px; border: 1px solid rgb(204, 204, 204); box-shadow: rgb(204, 204, 204) 0px 0px 3px; box-sizing: border-box; color: #333333; font-family: Menlo, Monaco, Consolas, 'Courier New', monospace; font-size: 13px; font-stretch: normal; line-height: 1.42857; margin-bottom: 10px; overflow: auto; padding: 9.5px; tab-size: 4; text-shadow: rgb(255, 255, 255) 0px 1px 0px; white-space: pre-wrap; word-break: break-all; word-wrap: break-word;">submission     inet  n       -       n       -       -       smtpd
  -o syslog_name=postfix/submission
  -o smtpd_sasl_auth_enable=yes
  -o smtpd_recipient_restrictions=permit_sasl_authenticated,reject
  -o milter_macro_daemon_name=ORIGINATING
smtps     inet  n       -       n       -       -       smtpd
  -o syslog_name=postfix/smtps
  -o smtpd_sasl_auth_enable=yes
  -o smtpd_recipient_restrictions=permit_sasl_authenticated,reject
  -o milter_macro_daemon_name=ORIGINATING
Now check the configuration using postfix check command.
Step 7 : Now configure Dovecot SASL for SMTP Auth. Open /etc/dovecot/conf.d/10-master.conf file, find “# Postfix smtp-auth” line ( line no:95 ) and add the below lines.
# Postfix smtp-auth
unix_listener /var/spool/postfix/private/auth {mode = 0660
user = postfix
group = postfix
}</pre>
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<span style="font-family: Verdana, Geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">Now check the configuration using <b><span style="color: #990000;">postfix check</span></b> command.</span></span></div>
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<span style="font-family: Verdana, Geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">Step 7 : Now configure Dovecot SASL for SMTP Auth. Open <b><span style="color: #990000;">/etc/dovecot/conf.d/10-master.conf</span></b> file, find "<b><span style="color: #990000;"># Postfix smtp-auth</span></b>" line ( line no:95 ) and add the below lines.</span></span></div>
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<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="font-family: Trebuchet MS, sans-serif; font-size: medium;"><span style="line-height: 15.6px;"><span style="color: white;"># Postfix smtp-auth
</span><span style="color: lime;">unix_listener /var/spool/postfix/private/auth {mode = 0660
</span><span style="color: white;">user = postfix
group = postfix
}</span></span></span></pre>
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<span style="font-family: Verdana, Geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;"><span style="color: #222222;">Step 8 : Open </span><b><span style="color: #990000;">/etc/dovecot/conf.d/10-auth.conf</span></b><span style="color: #222222;"> file, find "<b>auth_mechanisms = plain</b>" ( Line no: 100 ) and add login to the value like below.</span></span></span></div>
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<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="font-family: Trebuchet MS, sans-serif; font-size: medium;"><span style="line-height: 15.6px;"><span style="color: lime;">auth_mechanisms</span><span style="color: white;"> = plain login</span></span></span></pre>
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<span style="color: #222222; font-family: Verdana, Geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">Step 9 : Postfix configuration is over. Now restart both postfix and dovecot services and enable auto start</span></span><span style="color: #222222; font-family: Verdana, Geneva, sans-serif; line-height: normal;"><span style="font-size: 15px; line-height: 26px;">.</span></span></div>
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<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="font-family: Trebuchet MS, sans-serif; font-size: medium;"><span style="line-height: 15.6px;"><span style="color: orange;">[root@mail ~]# systemctl restart postfix
</span><span style="color: white;">[root@mail ~]# systemctl enable postfix
</span><span style="color: lime;">[root@mail ~]# systemctl restart dovecot
</span><span style="color: orange;">[root@mail ~]# systemctl enable dovecot</span></span></span></pre>
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<span style="color: #222222; font-family: Verdana, Geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">Step 10 : Add the firewall rules to allow <b>25, 587 and 465</b> ports</span></span><span style="color: black; font-family: 'Times New Roman'; font-size: 15px; line-height: 26px;">.</span></div>
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<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="font-family: Trebuchet MS, sans-serif; font-size: medium;"><span style="line-height: 15.6px;"><span style="color: white;">[root@mail ~]# firewall-cmd --permanent --add-service=smtp
</span><span style="color: lime;">[root@mail ~]# firewall-cmd --permanent --add-port=587/tcp
</span><span style="color: white;">[root@mail ~]# firewall-cmd --permanent --add-port=465/tcp
</span><span style="color: orange;">[root@mail ~]# firewall-cmd --reload</span></span></span></pre>
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<span style="font-family: Verdana, Geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;"><span style="color: #222222;">Now start testing connectivity for each ports 25,587 and 465 using telnet and make sure you are getting </span><span style="color: #990000;"><b>AUTH PLAIN LOGIN</b></span><span style="color: #222222;"> line after issuing <b>ehlo mail.hackthesec.co.in </b>command in telnet</span></span></span><span style="color: black; font-family: 'Times New Roman'; font-size: 15px; line-height: 26px;">.</span></div>
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<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="font-family: Trebuchet MS, sans-serif; font-size: medium;"><span style="line-height: 15.6px;"><span style="color: white;">[root@mail ~]# </span><span style="color: lime;">telnet mail.hackthesec.co.in 465</span><span style="color: white;">
Trying 172.27.0.51...
Connected to mail.hackthesec.co.in.
Escape character is '^]'.
</span><span style="color: orange;">220 mail.hackthesec.co.in ESMTP Postfix
</span><span style="color: white;">ehlo mail.hackthesec.co.in</span></span></span></pre>
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<span style="color: #0b5394; font-family: Verdana, Geneva, sans-serif; font-size: large;"><span style="line-height: 26px;"><b><u>Step 3 : Dovecot configuration</u></b></span></span></div>
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<span style="color: #222222; font-family: Verdana, Geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">Start configuring Dovecot</span></span><span style="color: black; font-family: 'Times New Roman'; font-size: 15px; line-height: 26px;">.</span></div>
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<span style="font-family: Verdana, Geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;"><span style="color: #222222;">Step 11 : Open </span><b><span style="color: #990000;">/etc/dovecot/conf.d/10-mail.conf</span></b><span style="color: #222222;"> file, find <b>#mail_location =</b> (line no : 30 ) and add the same directory which is given to home_mailbox in the postfix config file ( Step 5)</span></span></span><span style="font-size: 15px; line-height: 26px;">.</span></div>
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<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="font-family: Trebuchet MS, sans-serif; font-size: medium;"><span style="line-height: 15.6px;"><span style="color: white;">mail_location = </span><span style="color: lime;">maildir:~/mail</span></span></span></pre>
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<span style="font-family: Verdana, Geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;"><span style="color: #222222;">Step 12 : Open </span><b><span style="color: #990000;">/etc/dovecot/conf.d/20-pop3.conf</span></b><span style="color: #222222;"> file, find and uncomment the below line ( line no : 50 )</span></span></span><span style="color: black; font-family: 'Times New Roman'; font-size: 15px; line-height: 26px;">.</span></div>
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<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: lime; font-family: Trebuchet MS, sans-serif; font-size: medium;"><span style="line-height: 15.6px;">pop3_uidl_format = %08Xu%08Xv</span></span></pre>
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<span style="color: #222222; font-family: Verdana, Geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">Step 13 : Restart dovecot service</span></span><span style="color: black; font-family: 'Times New Roman'; font-size: 15px; line-height: 26px;">.</span></div>
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<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="font-family: Trebuchet MS, sans-serif; font-size: medium;"><span style="line-height: 15.6px;"><span style="color: white;">[root@mail ~]# </span><span style="color: lime;">systemctl restart dovecot</span></span></span></pre>
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<span style="color: #222222; font-family: Verdana, Geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">Step 14 : Add firewall rules to allow 110,143,993 and 995</span></span><span style="color: black; font-family: 'Times New Roman'; font-size: 15px; line-height: 26px;">.</span></div>
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<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="font-family: Trebuchet MS, sans-serif; font-size: medium;"><span style="line-height: 15.6px;"><span style="color: lime;">[root@mail ~]# firewall-cmd --permanent --add-port=110/tcp
</span><span style="color: white;">[root@mail ~]# firewall-cmd --permanent --add-service=pop3s
</span><span style="color: orange;">[root@mail ~]# firewall-cmd --permanent --add-port=143/tcp
</span><span style="color: white;">[root@mail ~]# firewall-cmd --permanent --add-service=imaps
[root@mail ~]# firewall-cmd --reload</span></span></span></pre>
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<span style="color: #222222; font-family: Verdana, Geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">Check the connectivity for the ports 110,143,993 and 995 using telnet</span></span><span style="color: black; font-family: 'Times New Roman'; font-size: 15px; line-height: 26px;">.</span></div>
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<span style="color: #0b5394; font-family: Verdana, Geneva, sans-serif; font-size: large;"><span style="line-height: 26px;"><b><u>Step 4 : User creation</u></b></span></span></div>
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<span style="color: #222222; font-family: Verdana, Geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">Now create user for testing .</span></span></div>
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<span style="font-family: Verdana, Geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;"><span style="color: #222222;">Step 15 : Create user with </span><b><span style="color: #990000;">/sbin/nologin</span></b><span style="color: #222222;"> shell to restrict login access</span></span></span><span style="font-size: 15px; line-height: 26px;">.</span></div>
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<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="font-family: Trebuchet MS, sans-serif; font-size: medium;"><span style="line-height: 15.6px;"><span style="color: lime;">[root@mail ~]# useradd -m john -s /sbin/nologin
</span><span style="color: white;">[root@mail ~]# passwd hackthesec</span></span></span></pre>
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<span style="color: #222222; font-family: Verdana, Geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">Mail server is ready now, Configure user in your mail client and test send/receive</span></span><span style="color: black; font-family: 'Times New Roman'; font-size: 15px; line-height: 26px;">.</span></div>
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<img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi-KvSTpPDbIqW1IOfpC424M9kQxnYaFzCZG7wO9XNDKTPS6lEYN_6UsN5XZrRvlDCj2ypN4O0teETtY3z2W6_uQjDAuwDLbCahUN7hvCt4qktVwfYNjZWBzEYa5_4RNUY8qrkrzNCKQZm1/s640/Setup+mail+server+on+centos+7_www.hackthesec.co.in.png" /></div>
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<a href="http://www.hackthesec.co.in/">www.hackthesec.co.in</a></div>
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How to setup mail server on centos 7

Setup mail server on centos 7 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. Be…