构建反病毒反垃圾邮件系统(六)

　　# dpkg -i *.deb

　　修改/etc/amavis/amavisd.conf：

　　@inet_acl = qw( 127/8 1.2.3.4/32 ); # 1.2.3.4 is your external ip .. because want maybe also accept mail from that interface, it's up to you.
　　$warnvirussender = 1; # I want to warn people, who have got virus.
　　$warnvirusrecip = 1; # I want to warn my users about virus send to them.
　　$warn_offsite = 1; # I want to warn senders/recipients, that are not located on my server
　　$mailfrom_notify_admin = 'virusalert@example.com'; #
　　$mailfrom_notify_recip = 'virusalert@example.com'; # Change these to the appropriate email-adresses, you wish to use as sender
　　$mailfrom_notify_spamadmin = 'spam.police@example.com'; # for spam and virus warnings
　　$hdrfrom_notify_sender = 'AMaViS (content filter) <postmaster@example.com>';
　　$virus_admin = 'virus-admin@example.com'; #
　　$spam_admin = 'spam-admin@example.com'; #

　　指定使用uvscan：

　　@av_scanners = (

　　['NAI McAfee AntiVirus (uvscan)', 'uvscan',
　　'--secure -rv --summary --noboot {}', [0], [13],
　　qr/(?x) Found (?:
　　\ the\ (.+)\ (?:virus|trojan) |
　　\ (?:virus|trojan)\ or\ variant\ ([^ ]+) |
　　:\ (.+)\ NOT\ a\ virus)/ ],

　　);

　　找到/etc/postfix/master.cf如下行：

　　smtp inet n - n - - smtpd

　　改为如下：

　　smtp inet n n n - - smtpd -o content_filter=smtp-amavis:[127.0.0.1]:10024
　　smtp-amavis unix - - n - 2 smtp
　　-o smtp_data_done_timeout=1200
　　-o disable_dns_lookups=yes
　　127.0.0.1:10025 inet n - n - - smtpd
　　-o local_recipient_maps=
　　-o smtpd_restriction_classes=
　　-o smtpd_client_restrictions=
　　-o smtpd_helo_restrictions=
　　-o smtpd_sender_restrictions=
　　-o smtpd_recipient_restrictions=permit_mynetworks,reject
　　-o strict_rfc821_envelopes=yes

　　重启postfix，这样在收到病毒邮件的时候能够在日志文件看到如下的信息：

　　Jul 16 15:34:22 xxx amavis[30997]: (30997-09) INFECTED (W32/Nimda.gen@MM), (?) -> <xxx@xxx.org>, quarantine virus-20030716-153422-30997-09, Message-ID: <20030716073414.520D3E5C2F@xxx>

　　三、防垃圾邮件部分

　　垃圾邮件的防范必须掌握好尺度，postfix本身提供了header_check、body_check、access、classes等方式来拒绝邮件，可以参考如下地址的样例，结合自己的情况进行修改也能阻止一部分垃圾邮件：

　　http://www.XXXX.com/guides/postfix_uce_header.html
　　http://www.XXXX.com/guides/postfix_uce_body.html
　　http://www.XXXX.com/guides/postfix_uce_access.html
　　http://www.XXXX.com/guides/postfix_uce_class.html

　　不过以上配置文件需要管理员根据自己情况手工进行修改，如果直接采用的话，那么国内很多邮件你将收不到。

　　SpamAssassin和AMaViS可以很好的结合，它能够帮管理员自动处理一些垃圾邮件。SpamAssassin很有趣，它对解码后的邮件进行扫描后打分，如果分数达到用户指定的分数，那么就认为是垃圾邮件，而且它还有学习功能，管理员也可以自己重新定义各种分值或自定义分值。

　　1、SpamAssassin的安装

　　由于已经安装了AMaViS，所以自然就选择了SpamAssassin。SpamAssassin可以通过CPAN安装：

　　# perl -MCPAN -e shell
　　install Mail::SpamAssassin

　　2、SpamAssassin配置

　　创建/var/lib/amavis/.spamassassin/user_prefs文件：

　　# SpamAssassin config file for version 2.5x
　　# generated by http://www.yrex.com/spam/spamconfig.php (version 1.01)

　　# How many hits before a message is considered spam.
　　required_hits 5.0

　　# Whether to change the subject of suspected spam
　　rewrite_subject 1

　　# Text to prepend to subject if rewrite_subject is used
　　subject_tag *****SPAM*****

　　# Encapsulate spam in an attachment
　　report_safe 1

　　# Use terse version of the spam report
　　use_terse_report 0

　　# Enable the Bayes system
　　use_bayes 1

　　# Enable Bayes auto-learning
　　auto_learn 1

　　# Enable or disable network checks
　　skip_rbl_checks 1
　　use_razor2 0
　　use_dcc 0
　　use_pyzor 0

　　# Mail using languages used in these country codes will not be marked
　　# as being possibly spam in a foreign language.
　　# - chinese english
　　ok_languages zh en