WAF原理入门：http://www.freebuf.com/articles/web/18084.html

WAF类型包括硬件WAF、云WAF、基于主机Agent WAF、开源WAF、反向代理集群WAF。

硬件WAF行业老大是imperva，优点是动态特征创建，缺点是？？？

硬件WAF国内是绿盟，原理是基于规则库，但逐步淘汰？？？

云WAF有阿里云盾，维护方便？？？

开源WAF是modsecurity，？？？http://www.freebuf.com/articles/web/63076.html

反向代理集群WAF？？？http://www.freebuf.com/video/127713.html

绕过WAF：http://www.freebuf.com/articles/web/8773.html

http://www.freebuf.com/articles/web/5908.html

http://www.freebuf.com/sectool/5263.html

http://www.freebuf.com/articles/1000.html

http://www.freebuf.com/articles/web/81959.html

http://www.freebuf.com/sectool/69988.html

http://www.freebuf.com/articles/web/36683.html

http://www.freebuf.com/articles/web/20282.html

http://www.freebuf.com/articles/web/10099.html

http://www.freebuf.com/sectool/127001.html

http://www.freebuf.com/sectool/106747.html

WAF