我已阅读以下教程https://wiki.archlinux.org/index.php/Wireless_network_configuration#Get_the_name_of_the_interface
据我了解，关键步骤是运行wpa_supplicant然后dhclient
包含的输出wpa_supplicant：
...
wlp12s0: WPA: CTRL-EVENT-CONNECTED - Connection to ... completed ...
wlp12s0: WPA: Group rekeying completed with ... [GTK=TKIP]
...
然后我执行了：
$ sudo iw dev wlp12s0 link
Connected to ... (on wlp12s0)
SSID: ...
freq: ...
...
然后：
$ sudo dhclient -v wlp12s0
Internet Systems Consortium DHCP Client 4.3.3
Copyright 2004-2015 Internet Systems Consortium.
All rights reserved.
For info, please visit https://www.isc.org/software/dhcp/
Listening on LPF/wlp12s0/00:23:4e:07:a1:e5
Sending on LPF/wlp12s0/00:23:4e:07:a1:e5
Sending on Socket/fallback
DHCPREQUEST of 192.168.1.67 on wlp12s0 to 255.255.255.255 port 67 (xid=0x75d51110)
DHCPREQUEST of 192.168.1.67 on wlp12s0 to 255.255.255.255 port 67 (xid=0x75d51110)
DHCPDISCOVER on wlp12s0 to 255.255.255.255 port 67 interval 3 (xid=0x69d6c72f)
DHCPDISCOVER on wlp12s0 to 255.255.255.255 port 67 interval 7 (xid=0x69d6c72f)
DHCPDISCOVER on wlp12s0 to 255.255.255.255 port 67 interval 13 (xid=0x69d6c72f)
DHCPDISCOVER on wlp12s0 to 255.255.255.255 port 67 interval 18 (xid=0x69d6c72f)
DHCPDISCOVER on wlp12s0 to 255.255.255.255 port 67 interval 20 (xid=0x69d6c72f)
DHCPDISCOVER on wlp12s0 to 255.255.255.255 port 67 interval 7 (xid=0x69d6c72f)
DHCPDISCOVER on wlp12s0 to 255.255.255.255 port 67 interval 14 (xid=0x69d6c72f)
DHCPDISCOVER on wlp12s0 to 255.255.255.255 port 67 interval 7 (xid=0x69d6c72f)
DHCPDISCOVER on wlp12s0 to 255.255.255.255 port 67 interval 8 (xid=0x69d6c72f)
DHCPDISCOVER on wlp12s0 to 255.255.255.255 port 67 interval 13 (xid=0x69d6c72f)
DHCPDISCOVER on wlp12s0 to 255.255.255.255 port 67 interval 15 (xid=0x69d6c72f)
DHCPDISCOVER on wlp12s0 to 255.255.255.255 port 67 interval 8 (xid=0x69d6c72f)
DHCPDISCOVER on wlp12s0 to 255.255.255.255 port 67 interval 8 (xid=0x69d6c72f)
DHCPDISCOVER on wlp12s0 to 255.255.255.255 port 67 interval 8 (xid=0x69d6c72f)
DHCPDISCOVER on wlp12s0 to 255.255.255.255 port 67 interval 8 (xid=0x69d6c72f)
DHCPDISCOVER on wlp12s0 to 255.255.255.255 port 67 interval 17 (xid=0x69d6c72f)
DHCPDISCOVER on wlp12s0 to 255.255.255.255 port 67 interval 14 (xid=0x69d6c72f)
DHCPDISCOVER on wlp12s0 to 255.255.255.255 port 67 interval 12 (xid=0x69d6c72f)
DHCPDISCOVER on wlp12s0 to 255.255.255.255 port 67 interval 9 (xid=0x69d6c72f)
DHCPDISCOVER on wlp12s0 to 255.255.255.255 port 67 interval 10 (xid=0x69d6c72f)
DHCPDISCOVER on wlp12s0 to 255.255.255.255 port 67 interval 11 (xid=0x69d6c72f)
DHCPDISCOVER on wlp12s0 to 255.255.255.255 port 67 interval 21 (xid=0x69d6c72f)
DHCPDISCOVER on wlp12s0 to 255.255.255.255 port 67 interval 19 (xid=0x69d6c72f)
DHCPDISCOVER on wlp12s0 to 255.255.255.255 port 67 interval 15 (xid=0x69d6c72f)
DHCPDISCOVER on wlp12s0 to 255.255.255.255 port 67 interval 15 (xid=0x69d6c72f)
No DHCPOFFERS received.
Trying recorded lease 192.168.1.67
RTNETLINK answers: File exists
PING 192.168.1.1 (192.168.1.1) 56(84) bytes of data.
--- 192.168.1.1 ping statistics ---
1 packets transmitted, 0 received, +1 errors, 100% packet loss, time 0ms
bound: renewal in 42208 seconds.
获得IP。
但有时输出dhclient看起来是这样的：
Internet Systems Consortium DHCP Client 4.3.3
Copyright 2004-2015 Internet Systems Consortium.
All rights reserved.
For info, please visit https://www.isc.org/software/dhcp/
Listening on LPF/wlp12s0/00:23:4e:07:a1:e5
Sending on LPF/wlp12s0/00:23:4e:07:a1:e5
Sending on Socket/fallback
DHCPDISCOVER on wlp12s0 to 255.255.255.255 port 67 interval 3 (xid=0x37f4762)
DHCPDISCOVER on wlp12s0 to 255.255.255.255 port 67 interval 6 (xid=0x37f4762)
DHCPDISCOVER on wlp12s0 to 255.255.255.255 port 67 interval 11 (xid=0x37f4762)
DHCPREQUEST of 192.168.1.67 on wlp12s0 to 255.255.255.255 port 67 (xid=0x62477f03)
DHCPOFFER of 192.168.1.67 from 192.168.1.1
DHCPACK of 192.168.1.67 from 192.168.1.1
bound to 192.168.1.67 -- renewal in 37520 seconds.
这是否意味着IP192.168.1.67已分配或未分配？抱歉，我不知道成功的输出是什么样子的。无论如何，此后我无法 ping 通任何网站。但我可以从家里的另一台电脑上 ping 通它：
$ ping 192.168.1.67
PING 192.168.1.67 (192.168.1.67) 56(84) bytes of data.
64 bytes from 192.168.1.67: icmp_seq=206 ttl=64 time=213 ms
64 bytes from 192.168.1.67: icmp_seq=327 ttl=64 time=318 ms
64 bytes from 192.168.1.67: icmp_seq=480 ttl=64 time=317 ms
完成后（大约花了 5 分钟。可以吗？）我跑了ifconfig并且iwconfig：
$ ifconfig
enp9s0 Link encap:Ethernet HWaddr 00:1c:23:82:98:53
UP BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)
Interrupt:17
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:65536 Metric:1
RX packets:40841 errors:0 dropped:0 overruns:0 frame:0
TX packets:40841 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1
RX bytes:3067719 (3.0 MB) TX bytes:3067719 (3.0 MB)
wlp12s0 Link encap:Ethernet HWaddr 00:23:4e:07:a1:e5
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:341 errors:0 dropped:0 overruns:0 frame:119856
TX packets:837 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:23190 (23.1 KB) TX bytes:86896 (86.8 KB)
Interrupt:17 Base address:0xc000
wlp12s0:avahi Link encap:Ethernet HWaddr 00:23:4e:07:a1:e5
inet addr:169.254.8.210 Bcast:169.254.255.255 Mask:255.255.0.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
Interrupt:17 Base address:0xc000
$ iwconfig
lo no wireless extensions.
wlp12s0 IEEE 802.11 ESSID:"Kazak"
Mode:Managed Frequency:2.417 GHz Access Point: D4:21:22:25:E3:04
Retry short limit:7 RTS thr:off Fragment thr:off
Power Management:off
enp9s0 no wireless extensions.
但没有互联网连接：
$ ping www.google.com
ping: unknown host www.google.com
我缺少什么？
PS 有线连接有效。