centeros7连接wifi

[root@localhost ~]# iw dev
phy#0
Interface wlp3s0
ifindex 2
wdev 0x1
addr 78:92:9c:71:ea:1e
type managed
[root@localhost ~]# ip link set wlp3s0 up
[root@localhost ~]# ip link show wlp3s0
2: wlp3s0: mtu 1500 qdisc mq state UP mode DORMANT qlen 1000
    link/ether 78:92:9c:71:ea:1e brd ff:ff:ff:ff:ff:ff
[root@localhost ~]# iw wlp3s0 link
Connected to 74:ea:3a:4f:72:b6 (on wlp3s0)
SSID: czm_wifi
freq: 2452
RX: 165329 bytes (974 packets)
TX: 1272 bytes (13 packets)
signal: -47 dBm
tx bitrate: 6.5 MBit/s MCS 0


bss flags: short-preamble short-slot-time
dtim period: 0
beacon int: 100
[root@localhost ~]# iw wlp3s0 scan | grep SSID
SSID: czm_wifi
SSID: youdulianjie
SSID: 2015Lucky~
SSID: iyer
SSID: Tenda_13F6F8
SSID: Tenda_21B410
SSID: quan
SSID: LieBaoWiFi529
SSID: ChinaNet-B32s
SSID: PC-ADAS
SSID: Xiaomi_6CD1
SSID: iTV-B32s
SSID: zhou801
[root@localhost ~]# wpa_supplicant -B -i wlp3s0 -c <(wpa_passphrase "czm_wifi" "asdfgh123")
Successfully initialized wpa_supplicant
[root@localhost ~]# dhclient wlp3s0
[root@localhost ~]# ip addr show wlp3s0
2: wlp3s0: mtu 1500 qdisc mq state DOWN qlen 1000
    link/ether 78:92:9c:71:ea:1e brd ff:ff:ff:ff:ff:ff