如果要让 Amavisd 对本地外发的邮件不做邮件内容过滤和病毒扫描，可以在 policy_bank 里增加参数：
文件： /etc/amavisd.conf

$policy_bank{'MYNETS'} = {   # mail originating from @mynetworks
  originating => 1,  # is true in MYNETS by default, but let's make it explicit
  os_fingerprint_method => undef,  # don't query p0f for internal clients

  #
  # 增加以下三个参数
  #
  bypass_spam_checks_maps   => [1],  # don't spam-check internal mail
  bypass_banned_checks_maps => [1],  # don't banned-check internal mail
  bypass_header_checks_maps => [1],  # don't header-check internal mail
};

hi bibby，这个设置后，感觉没作用，一个15M的附件，设置前和设置后的时间都是一样的