出网判断：

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