icmp：
ping ip/domain tracert ip/domain pathping ip/domain
tcp:
##vps 监听 ## tcp ##nc -lvvnp port telnet ip port nc -zv ip port
udp:
## vps 监听 ## udp ##nc -lvvnup port nc -zuv ip port
http/https:
curl http://xxx.xx.xx wget https://xxx.xx.xx
dns:
ping xxx.com nslookup xxx.com dig xxx.com
