3． tracert命令的主要功能是什么？有那些主要参数？各个参数的作用是什么？

tracert是检测你的机器通到几个路由中转到目的地IP的命令。
主要参数和参数作用如下:
-d Do not resolve addresses to hostnames.
-h maximum_hops Maximum number of hops to search for target.
-j host-list Loose source route along host-list (IPv4-only).
-w timeout Wait timeout milliseconds for each reply.
-R Trace round-trip path (IPv6-only).
-S srcaddr Source address to use (IPv6-only).
-4 Force using IPv4.
-6 Force using IPv6.