SMTP Configuration

[root@SysAdmin ~]# yum install postfix
 
Last metadata expiration check: 4:50:02 ago on Sun 29 Sep 2024 08:18:17 AM +06.
Dependencies resolved.
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 Package         Architecture   Version                 Repository         Size
================================================================================
Installing:
 postfix         x86_64         2:3.5.9-24.el9          appstream         1.4 M
 
Transaction Summary
================================================================================
Install  1 Package
 
Total download size: 1.4 M
Installed size: 4.4 M
Is this ok [y/N]: y
Downloading Packages:
postfix-3.5.9-24.el9.x86_64.rpm                 425 kB/s | 1.4 MB     00:03
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Total                                           334 kB/s | 1.4 MB     00:04
Running transaction check
Transaction check succeeded.
Running transaction test
Transaction test succeeded.
Running transaction
  Preparing        :                                                        1/1
  Running scriptlet: postfix-2:3.5.9-24.el9.x86_64                          1/1
  Installing       : postfix-2:3.5.9-24.el9.x86_64                          1/1
  Running scriptlet: postfix-2:3.5.9-24.el9.x86_64                          1/1
  Verifying        : postfix-2:3.5.9-24.el9.x86_64                          1/1
 
Installed:
  postfix-2:3.5.9-24.el9.x86_64
 
Complete!
 
[root@SysAdmin ~]# rpm -qa | grep postfix
 
postfix-3.5.9-24.el9.x86_64
 
[root@SysAdmin ~]# cd /etc/postfix/
 
[root@SysAdmin postfix]# ls
access            generic        master.cf        relocated
canonical         header_checks  master.cf.proto  sasl_passwd
dynamicmaps.cf    main.cf        postfix-files    transport
dynamicmaps.cf.d  main.cf.proto  postfix-files.d  virtual
 
[root@SysAdmin postfix]# vi main.cf
 
relayhost = [smtp.gmail.com]:587
myhostname = SysAdmin
 
[root@SysAdmin postfix]# vi main.cf
 
#Location of sasl_passwd we saved
smtp_sasl_password_maps = hash:/etc/postfix/sasl/sasl_passwd
 
#Enables SASL authentication for postfix
smtp_sasl_auth_enable = yes
smtp_tls_security_level = encrypt
 
#Disallow methods that allow anonymous authentication
smtp_sasl_security_options = noanonymous
 
[root@SysAdmin postfix]# pwd
/etc/postfix
[root@SysAdmin postfix]# mkdir sasl
[root@SysAdmin postfix]# cd sasl/
[root@SysAdmin sasl]# touch sasl_passwd
[root@SysAdmin sasl]# ls
sasl_passwd
 
#######################################################################
 
Enable two factor authenticate
App passwords - smtp
your app password for your device - dnbm nrxm kiam fomx
 
[root@SysAdmin sasl]# vi sasl_passwd
 
[smtp.gmail.com]:587 dev609dev@gmail.com:dnbmnrxmkiamfomx
 
#######################################################################
 
[root@SysAdmin sasl]# pwd
/etc/postfix/sasl
[root@SysAdmin sasl]# ls -ltr
total 4
-rw-r--r--. 1 root root 58 Sep 29 13:31 sasl_passwd
 
[root@SysAdmin sasl]# postmap sasl_passwd
postmap: warning: /etc/postfix/main.cf, line 752: overriding earlier entry: smtp_tls_security_level=may
 
[root@SysAdmin sasl]# ls -ltr
total 12
-rw-r--r--. 1 root root    58 Sep 29 13:31 sasl_passwd
-rw-r--r--. 1 root root 12288 Sep 29 13:35 sasl_passwd.db
 
[root@SysAdmin sasl]# chmod 600 *
[root@SysAdmin sasl]# ls -ltr
total 12
-rw-------. 1 root root    58 Sep 29 13:31 sasl_passwd
-rw-------. 1 root root 12288 Sep 29 13:35 sasl_passwd.db
 
[root@SysAdmin sasl]# systemctl start postfix.service
 
####################################################
 
To send an email using Linux terminal
 
echo "Test Mail" | mail -s "Postfix TEST" dev609dev@gmail.com
 
echo "Message Body Here" | mailx -s "Subject Here" -a backup_21-09-18.log dev609dev@gmail.com
 
####################################################
 
For not to get any notification on the command line:
 
#smtp_tls_security_level = may
 
[root@SysAdmin postfix]# systemctl restart postfix.service