在使用SecureCRT连接虚拟机时，连接出现异常，很久都没连接上，但是也没有出现报错
直接在虚拟机上ping本地的IP，发现出现了DUP!的状态

[root@test ~]# ping 192.168.133.1
PING 192.168.133.1 (192.168.133.1) 56(84) bytes of data.
64 bytes from 192.168.133.1: icmp_seq=1 ttl=128 time=0.209 ms
64 bytes from 192.168.133.1: icmp_seq=1 ttl=128 time=0.588 ms (DUP!)
64 bytes from 192.168.133.1: icmp_seq=2 ttl=128 time=0.157 ms
64 bytes from 192.168.133.1: icmp_seq=2 ttl=128 time=0.560 ms (DUP!)
64 bytes from 192.168.133.1: icmp_seq=3 ttl=128 time=0.229 ms
64 bytes from 192.168.133.1: icmp_seq=3 ttl=128 time=0.792 ms (DUP!)
64 bytes from 192.168.133.1: icmp_seq=4 ttl=128 time=0.166 ms
64 bytes from 192.168.133.1: icmp_seq=4 ttl=128 time=2.02 ms (DUP!)
64 bytes from 192.168.133.1: icmp_seq=5 ttl=128 time=0.152 ms
64 bytes from 192.168.133.1: icmp_seq=5 ttl=128 time=0.476 ms (DUP!)
64 bytes from 192.168.133.1: icmp_seq=6 ttl=128 time=0.520 ms
64 bytes from 192.168.133.1: icmp_seq=6 ttl=128 time=0.535 ms (DUP!)
找了找网上的解决方法：
1.清空/etc/udev/rules.d/70-persistent-net.rules ：
[root@test ~]# cd /etc/udev/rules.d/
[root@test rules.d]# ll
total 4
-rw-r--r--. 1 root root 628 Sep 26  2019 70-persistent-ipoib.rules
[root@test rules.d]# >70-persistent-ipoib.rules
[root@test rules.d]# ll
total 0
-rw-r--r--. 1 root root 0 Feb 10 18:10 70-persistent-ipoib.rules


2.停掉NetworkManager服务
[root@test]# service NetworkManager stop
Stopping NetworkManager daemon:                            [  OK  ]

3.重启网络服务
[root@orcldg rules.d]# service network restart
Restarting network (via systemctl):                        [  OK  ]


[root@test rules.d]# ping 192.168.133.1
PING 192.168.133.1 (192.168.133.1) 56(84) bytes of data.
64 bytes from 192.168.133.1: icmp_seq=1 ttl=128 time=0.438 ms
64 bytes from 192.168.133.1: icmp_seq=2 ttl=128 time=0.489 ms
64 bytes from 192.168.133.1: icmp_seq=3 ttl=128 time=0.321 ms
64 bytes from 192.168.133.1: icmp_seq=4 ttl=128 time=0.401 ms
64 bytes from 192.168.133.1: icmp_seq=5 ttl=128 time=0.811 ms


网络状态正常，使用SecureCRT连接上了虚拟机