Mail Server : Add Mail User Accounts (Virtual User)2020/11/12

	Add Mail User Accounts to use Mail Service. This example is for the case you use virtual mail-user accounts, not use OS accounts.
[1]	Configure basic Postfix settings and basic Dovecot settings first.
[2]	Configure additional settings to Postfix and Dovecot.

# create a admin user for virtual mailboxes

[root@mail ~]#

useradd --uid 20000 --shell /sbin/nologin vmail

[root@mail ~]#

vi /etc/postfix/main.cf

# line 183: comment out

mydestination = $myhostname, localhost.$mydomain, localhost, $mydomain

# line 438: change

home_mailbox =

/home/vmail/%d/%n/Maildir

# add to the end

# if specify multiple domains, specify comma or space separated
virtual_mailbox_domains = srv.world, virtual.host
virtual_mailbox_base = /home/vmail
virtual_mailbox_maps = hash:/etc/postfix/virtual-mailbox
virtual_uid_maps = static:20000
virtual_gid_maps = static:20000

[root@mail ~]#

vi /etc/dovecot/conf.d/10-auth.conf

# line 100: add

auth_mechanisms =

cram-md5

plain login

# line 122: comment out

!include auth-system.conf.ext

# line 125: uncomment

!include auth-passwdfile.conf.ext

# line 128: uncomment

!include auth-static.conf.ext

[root@mail ~]#

vi /etc/dovecot/conf.d/auth-passwdfile.conf.ext

# line 8: change

passdb {
  driver = passwd-file
  args = scheme=CRAM-MD5 username_format=%u /etc/dovecot/users

# line 11: comment out all [userdb] section

#userdb {
#  driver = passwd-file
#  args = username_format=%u /etc/dovecot/users
#.....
#.....
#}

[root@mail ~]#

vi /etc/dovecot/conf.d/auth-static.conf.ext

# line 21-24: uncomment and change

userdb {
  driver = static
  args = uid=vmail gid=vmail home=/home/vmail/%d/%n
}

[root@mail ~]#

vi /etc/dovecot/conf.d/10-mail.conf

# line 30: change

mail_location = maildir:

/home/vmail/%d/%n/Maildir

[root@mail ~]#

systemctl restart postfix dovecot

[3]	Add virtual mail user accounts.

[root@mail ~]#

vi /etc/postfix/virtual-mailbox

# create new

# [user account] [mailbox]

cent@srv.world   srv.world/cent/Maildir/
fedora@srv.world   srv.world/fedora/Maildir/
redhat@virtual.host   virtual.host/redhat/Maildir/

[root@mail ~]#

postmap /etc/postfix/virtual-mailbox

# generate encrypted password

[root@mail ~]#

doveadm pw -s CRAM-MD5

Enter new password:
Retype new password:
{CRAM-MD5}xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

[root@mail ~]#

vi /etc/dovecot/users

# create new

# [user account] [password]

cent@srv.world:{CRAM-MD5}xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
fedora@srv.world:{CRAM-MD5}xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
redhat@virtual.host:{CRAM-MD5}xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

[4]	That's OK. Verify to test to send emails with E-Mail client. For settings on this example, specify email address for [Username] on Email Client settings.

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