【摘要】 随着校园网规模的扩大,有必要采用NAT技术来解决所获分配合法IP地址有限的问题。首先,该文阐述了采用Netfilter/iptables技术来实现NAT的缘由,并分析了此项技术在Linux内核2.4中的一个重要新特性,即“连接跟踪”;接着,着重讨论了提高基于配有Linux操作系统的普通PC机上的NAT性能的方法,包括重编内核,防止空对话及修改tcp连接超时设定;最后,通过一组系统状态监测曲线图证明这样一个廉价系统作为一些昂贵的路由设备的替代是稳定可靠的。更多还原

【Abstract】 With the enlargement of the scale of the campus networks,it’s required resorting to NAT technology as the solutions for the limit of the IP addresses that are legal,officially assigned.The paper first points out the reasons we adopt Netfilter /iptables and analyses″Connection tracking″,which is a new and important feature of netfilter in kernel2.4,then focuses on the methods to improve the performance of NAT based on an ordinary PC with Linux,including recompiling kernel,preventing idle sessions and resetting timeouts of tcp connection.At the end of the paper,such a low-cost system,as the replacement for some expensive special router devices,proves to be stable and reliable,accord-ing to a set of monitor graphs describing the system states.更多还原