ping command
You can know what system the other party is by checking the ttl
linux 64
window 128
unix 255
-t means keep pinging
ping -l 200 10.7.1.53 means sending a large packet to ping
Send to the first router
LAN failure ping LAN timed out
pathping can see the packet loss situation and understand how many routers to reach the target machine
tracert
ping pingpath tracert traceroute all use icmp protocol