nc 查看tcp和udp端口是否开启

telnet只能看tcp
root@performance:~# telnet 192.168.80.104 9108
Trying 192.168.80.104...
Connected to 192.168.80.104.
Escape character is '^]'.

nc既可以看tcp也可以看udp
tcp
root@performance:~# nc -vz 192.168.80.104 9108
192.168.80.104: inverse host lookup failed: Unknown host
(UNKNOWN) [192.168.80.104] 9108 (?) open
udp
root@performance:~# nc -uvz 192.168.80.93 6688
192.168.80.93: inverse host lookup failed: Unknown host
(UNKNOWN) [192.168.80.93] 6688 (?) open