CentOS + Postfix + Dovecot で、なぜか root がメールを受信してしまう場合のメモ

(CentOS6.3, Postfix2.6.6, Dovecot?)

症状

たとえば info@hoge.com 宛にメールを送信したのに、
root@hoge.com が受信してしまう。

原因

root にエイリアス貼られてる

cat /etc/aliases

#
#  Aliases in this file will NOT be expanded in the header from
#  Mail, but WILL be visible over networks or from /bin/mail.
#
#       >>>>>>>>>>      The program "newaliases" must be run after
#       >> NOTE >>      this file is updated for any changes to
#       >>>>>>>>>>      show through to sendmail.
#

# Basic system aliases -- these MUST be present.
mailer-daemon:  postmaster
postmaster:     root

# General redirections for pseudo accounts.
bin:            root
daemon:         root
adm:            root
lp:             root
sync:           root
shutdown:       root
halt:           root
mail:           root
news:           root
uucp:           root
newsadm:        news
newsadmin:      news
usenet:         news
ftpadm:         ftp
ftpadmin:       ftp
ftp-adm:        ftp
ftp-admin:      ftp
www:            webmaster
webmaster:      root
noc:            root
security:       root
hostmaster:     root
info:           postmaster
marketing:      postmaster
sales:          postmaster
support:        postmaster


# trap decode to catch security attacks
decode:         root

# Person who should get root's mail
#root:          marc