摘要： 针对大型网络运营管理中通常需要了解网络中是否存在局域网的问题，提出一种探测大型网络中局域网的有无，并统计局域网内活动主机数的方法。采用网络包截获技术，并通过对截获包的序列号、源地址、目的地址、源端口、目的端口进行分析来实现主机的识别算法。在实际网络环境下长期运行的结果表明，以该算法开发的软件能够较准确地探测出大型网络内局域网的数目以及各局域网内的活动主机数目。

关键词: 局域网, 网络地址转换, TCP/IP协议, 主机探测

Abstract: There are many needs to know the existence of LAN in the management of big networks. Facing this problem, a technique to detect the existence of LAN in a large network is described, and the number of active hosts in the LAN is counted. The technique is based on the technology of packets capture. By processing the IP_SEQ, SRC_IP, SRC_PORT, DEST_IP, and DEST_PORT of the captured packets, those packets send from individual machines can be discriminated, and the number of machines can be determined. The implementation, tested on real network environment, can properly count the number of LAN in the network and the number of hosts behind a LAN, which demonstrates the feasibility of the algorithm.

Key words: LAN, Network Address Translation(NAT), TCP/IP, hosts detection

中图分类号: 

• TP393