squid3.0及以后的版本相对于squid2系列有所改变，主要是把squid2系列的源代码由C换为了C＋＋，同时增加了一些rfc文档里所描述的功能-squid3.0 and subsequent versions as opposed to a change in squid2 series is meant to give the series squid2 source code from the C-for for C　　, while increasing the number of rfc document described the function of