过滤(Filter)是一种相对来说最简单却很直接的处理垃圾邮件技术。这种技术主要用于接收系统(MUA,如 OutlookExpress 或者 MTA,如 sendmail)来辨别和处理垃圾邮件。从应用情况来看,这种技术也是使用最广泛的,比如很多邮件服务器上的反垃圾邮件插件、反垃圾邮件网关、客户端上的反垃圾邮件功能等,都是采用的过滤技术。过滤技术包括:关键词过滤;黑白名单;HASH 技术;基于规则的过滤;智能和概率系统。目前的问题是,人们认为过滤器能有效阻止垃圾邮件。实际上,垃圾邮件过滤器并不能有效阻止垃圾邮件,在多数案例中,垃圾邮件依然存在,依然穿过了网络,并且依然被传播。除非用户不介意 Filter (Filter) is a relatively simple but very direct treatment of spam technology. This technique is mainly used for receiving systems (MUA, such as Outlook Express or MTA, such as sendmail) to identify and deal with spam. From the application point of view, this technology is also the most widely used, such as many anti-spam mail server mail, anti-spam gateway, anti-spam features on the client, are used filtering technology. Filtering techniques include: keyword filtering; black and white lists; HASH technology; rule-based filtering; intelligent and probabilistic systems. The problem is that people think filters can effectively stop spam. In fact, spam filters do not stop spam effectively. In most cases, spam still exists, still traversing the network, and is still being broadcast. Unless the user does not mind