[1] [CITE[PostfixによるSMTPサーバの構築(CentOS標準版編)]]
([TIME[2007-06-04 20:19:06 +09:00]] 版)
<http://www.aconus.com/~oyaji/centos/smtp-centos.htm>

[2] [CITE@ja[「Postfix」の設定]]
([TIME[2008-06-15 21:12:03 +09:00]] 版)
<http://www.crimson-snow.net/hmsvr/centos/maild/postfix.html>

[3] [CITE[Postgrey(Postfix Greylisting Policy Server)日本語ポータル]]
([TIME[2009-01-15 16:27:12 +09:00]] 版)
<http://www.kozupon.com/postgrey/index.html>

[4] [CITE@en[Postgrey - Postfix Greylisting Policy Server]]
([TIME[2009-07-03 23:54:55 +09:00]] 版)
<http://postgrey.schweikert.ch/>