一、ping：測試本機至遠端電腦的網路連線是否暢通

Usage: ping [-t] [-a] [-n count] [-l size] [-f] [-i TTL] [-v TOS][-r count] [-s count] [[-j host-list] | [-k host-list]][-w timeout] destination-list

Options:
-t Ping the specified host until stopped. (持續測試直到按 CTRL+C為止，ping -t 140.126.110.21)  
     To see statistics and continue - type Control-Break;
     To stop - type Control-C.

-a Resolve addresses to hostnames. (進行反解DNS再 Ping, ping -a 140.126.110.21)

-n count Number of echo requests to send. (預設測試4次，可增加次數，ping -n 20  140.126.110.21)

-l size Send buffer size. (預設測試封包量為32Bytes，可改變封包大小，ping -l 200  140.126.110.21, 封包量越大，時間越久)

-f Set Don't Fragment(分散) flag in packet.(路由器不分散封包的傳送，限IPv4)

-i TTL Time To Live. (將「存活時間」欄位設為ttl所指定的值)

-v TOS Type Of Service. (將「服務類型」欄位設為tos所指定的值)

-r count Record route for count hops. (顯示封包到達目的地後回傳，所經過的count個節點，以確定發生問題的節點，ping -r 6 www.nctu.edu.tw)

-s count Timestamp for count hops.

-j host-list Loose source route(鬆散路由來源) along host-list. (用host-list 所指定的電腦清單的路徑來傳送封包。中介閘道(鬆散路由來源)可隔開連續的電腦，限IPv4。)

-k host-list Strict source route along host-list.(用host-list 所指定的電腦清單的路徑來傳送封包。中介閘道(嚴密路由來源)不可隔開連續的電腦，限IPv4)

-w timeout Timeout in milliseconds to wait for each reply.(指定逾時間隔，以毫秒計)