groupadd -g 5000 vmail
useradd -g vmail -u 5000 vmail
mkdir -p /var/mail/vhosts/example.com
mkdir -p /var/mail/vhosts/example2.com
chown vmail:vmail /var/mail/vhosts/example.com
chown vmail:vmail /var/mail/vhosts/example2.com

 /etc/postfix/main.cf:
      virtual_mailbox_domains = example.com, example2.com
      virtual_mailbox_base = /var/mail/vhosts
      virtual_mailbox_maps = hash:/etc/postfix/vmailbox
      virtual_minimum_uid = 100
      virtual_uid_maps = static:5000
      virtual_gid_maps = static:5000
      virtual_alias_maps = hash:/etc/postfix/virtual

 /etc/postfix/vmailbox:
     info@example.com    example.com/info/
     sales@example.com   example2.com/sales/
     info@example2.com    example2.com/info/
     sales@example2.com   example2.com/sales/
     # Comment out the entry below to implement a catch-all.
     # @example.com      example.com/catchall/

 /etc/postfix/virtual:
     # to direct virtual account traffic to a real system account
     postmaster@example.com postmaster

/etc/courier/authdaemonrc
  authmodulelist="authuserdb authpam"

postmap /etc/vmailbox
postmap /etc/virtual
/etc/init.d/postfix restart
/etc/init.d/courier-authdaemon restart
echo "First Post" | mail -s "Welcome" info@example.com
echo "First Post" | mail -s "Welcome" sales@example.com
echo "First Post" | mail -s "Welcome" info@example2.com
echo "First Post" | mail -s "Welcome" sales@example2.com
userdb "info@example.com" set uid=vmail gid=vmail home=/var/mail/vhosts/example.com/info mail=/var/mail/vhosts/example.com/info
userdbpw  | userdb "info@example.com" set systempw
userdb "sales@example.com" set uid=vmail gid=vmail home=/var/mail/vhosts/example.com/sales mail=/var/mail/vhosts/example.com/sales
userdbpw  | userdb "sales@example.com" set systempw
userdb "info@example2.com" set uid=vmail gid=vmail home=/var/mail/vhosts/example2.com/info mail=/var/mail/vhosts/example2.com/info
userdbpw  | userdb "info@example.com" set systempw
userdb "sales@example2.com" set uid=vmail gid=vmail home=/var/mail/vhosts/example2.com/sales mail=/var/mail/vhosts/example2.com/sales
userdbpw  | userdb "sales@example.com" set systempw
makeuserdb

# For some reason this setup may have problems with IMAP