Now logging …

LOCAL_CONFIG

F{PartSubjects} -o /etc/mail/subjects_rejects
HSubject:       $>CheckSubject

LOCAL_RULESETS

SCheckSubject
R$* $={PartSubjects} $* $: REJECTSUBJECT
R$* REJECTSUBJECT $*    $#error $: "553 Rejected , indicates spam Caused by Subject:"

[root@mx-ns mail]# cat /etc/mail/subjects_rejects
        master
        unsecured visa
        Invoice #
        Your Order #
[root@mx-ns mail]#

[root@mx-ns mail]# m4 /etc/mail/sendmail.mc > /etc/mail/sendmail.cf

[root@mx-ns mail]# service sendmail restart
sm-client を停止中:                                        [  OK  ]
sendmail を停止中:                                         [  OK  ]
sendmail を起動中:                                         [  OK  ]
sm-client を起動中:                                        [  OK  ]
[root@mx-ns mail]#

[root@mx-ns mail]# sendmail -bt
ADDRESS TEST MODE (ruleset 3 NOT automatically invoked)
Enter  

> CheckSubject master　※アクセス規制対象
CheckSubject       input: master
CheckSubject     returns: $# error $: "553 Rejected , indicates spam Caused by Subject:"
> CheckSubject test　※アクセス規制対象外
CheckSubject       input: test
CheckSubject     returns: test

メールクライアント（規制内容に抵触する件名 「Invoice # 1221」)で送信

[ment@log ~]$ mail testuser@simalab.com
Subject: Invoice # 1221
This is test1
.
EOT>

メールクライアント側に「553 5.0.0 Rejected , indicates sapm Caused by Subject:」が
エラーリターンされることを確認

The original message was received at Sun, 20 Mar 2016 11:27:27 +0900
from log.simalab.com [127.0.0.1]

   ----- The following addresses had permanent fatal errors -----

    (reason: 553 5.0.0 Rejected , indicates spamCaused by Subject:)

メールサーバ側のログ（件名でのアクセス制御が成功していることを確認）

Mar 20 11:27:33 mx-ns sendmail[7262]: u2K2RXie007262: ruleset=CheckSubject, arg1= Invoice # 1221, relay=[192.168.3.6], reject=553 5.0.0 Rejected , indicates spam Caused by Subject:
Mar 20 11:27:33 mx-ns sendmail[7262]: u2K2RXie007262: from=, size=659, class=0, nrcpts=1, msgid=<201603200227.u2K2RRuN004209@log.simalab.com>, proto=ESMTP, daemon=MTA, relay=[192.168.3.6]
Mar 20 11:27:33 mx-ns sendmail[7262]: u2K2RXie007262: to=, delay=00:00:00, pri=30659, stat=Rejected , indicates spam Caused by Subject:

メールクライアント（件名 normal mail)で送信

[ment@log ~]$ mail testuser@simalab.com
Subject: normal mail
this is normal mail
.
EOT

メールサーバ側のログ（件名でのアクセス制御が実施されず、受信が正常に成功していることを確認）

Mar 20 11:33:27 mx-ns sendmail[7265]: u2K2XR6O007265: from=, size=662, class=0, nrcpts=1, msgid=<201603200233.u2K2XLq7004256@log.simalab.com>, proto=ESMTP, daemon=MTA, relay=[192.168.3.6]
Mar 20 11:33:27 mx-ns sendmail[7266]: u2K2XR6O007265: to=, delay=00:00:00, xdelay=00:00:00, mailer=local, pri=30842, dsn=2.0.0, stat=Sent

[root@mx-ns mail]#  service sendmail reload