frank

SMTP邮件主题检测自定义策略内容：
CLIENT:any        SERVER:25
msg:"SMTP主题过滤"; content: "virus"; pcre:"/^Subject:/smi"; nocase;

POP3邮件主题检测自定义策略内容：
SERVER:110        CLIENT:any
msg:"POP3主题过滤"; content: "virus" ;pcre:"/^Subject:/smi"; nocase;