yum install -y nc
[root@Proxy ~]# nc -vuz 172.16.254.251 161
Ncat: Version 7.50 ( https://nmap.org/ncat )
Ncat: Connected to 172.16.254.251:161.
Ncat: UDP packet sent successfully
Ncat: 1 bytes sent, 0 bytes received in 2.04 seconds.
原文：https://www.cnblogs.com/leoshi/p/12670957.html