ubuntu-16.04.2-server-amd64 连接wifi

首先查看自己网卡的信息：一般人的都是eth0，和wlan0，但在Ubuntu Server 16.04里面变成了enp4s0和wlp5s0，算是第一个坑吧，
ubuntu@ubuntu:~$ ip addr
1: lo: mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: enp4s0: mtu 1500 qdisc noop state DOWN group default qlen 1000
link/ether 28:d2:44:98:33:2a brd ff:ff:ff:ff:ff:ff
3: wlp5s0: mtu 1500 qdisc mq state UP group default qlen 1000
link/ether 18:cf:5e:00:84:ba brd ff:ff:ff:ff:ff:ff
inet 192.168.224.102/24 brd 192.168.224.255 scope global wlp5s0
valid_lft forever preferred_lft forever
inet6 fe80::1acf:5eff:fe00:84ba/64 scope link
valid_lft forever preferred_lft forever

把WiFi-ssid和密码写入一个配置文件
wpa_passphrase ssid password > xxx.conf
编辑网络配置文件vi /etc/network/interfaces
source /etc/network/interfaces.d/*

# The loopback network interface
auto lo
iface lo inet loopback
auto wlp5s0
iface wlp5s0 inet dhcp
wpa-conf /home/ubuntu/xxx.conf
# The primary network interface
接下来有几种方法获取ip地址：
自动获取ip地址：如果不行可以先reboot一下
dhclient wlp5s0
或者手动获取ip：如果不行可以先reboot一下
-B - fork into background
-c filename - path to configuration file
-i interface - interface to listen on
wpa_supplicant -i wlp5s0 -c /home/ubuntu/xxx.conf