查看网卡状态
我们可以使用ifconfig命令查看当前的网卡状态信息。
root@raspberrypi:~# ifconfig
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.31.159 netmask 255.255.255.0 broadcast 192.168.31.255
inet6 fe80::a579:e25:d60e:838a prefixlen 64 scopeid 0x20<link>
ether b8:27:eb:08:b2:02 txqueuelen 1000 (Ethernet)
RX packets 42954 bytes 2101217 (2.0 MiB)
RX errors 0 dropped 27 overruns 0 frame 0
TX packets 292 bytes 26175 (25.5 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
inet6 ::1 prefixlen 128 scopeid 0x10<host>
loop txqueuelen 1000 (Local Loopback)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
wlan0: flags=4099<UP,BROADCAST,MULTICAST> mtu 1500
ether b8:27:eb:5d:e7:57 txqueuelen 1000 (Ethernet)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0其中eth0为有线网卡，lo代表127.0.0.1即localhost，wlan0代表无线网卡。
下表对参数做一下简单解释
| <> | UP 网卡已启用 BROADCAST 广播 LOOPBACK 本地访问 RUNNING 网卡正在运行 MULTICAST 多路广播 |
| mtu | MTU（Maximum Transmission Unit）最大传输单元 |
| inet | IPV4地址 |
| netmask | 网络掩码 |
| broadcast | 广播地址 |
| inet6 | IPV6地址 |
| prefixlen | 前缀长度 |
| ether | 网卡地址（MAC） |
| txqueuelen | 传输缓区长度大小意思 |
| RX packets bytes | 接收{数据包数量 数据包大小} |
| RX errors dropped overruns frame | 接收{错误数 丢包数 溢出数 框架} |
| TX packets bytes | 发送{数据包数量 数据包大小} |
| TX errors dropped overruns carrier collisions | 发送{错误数 丢包数 溢出数 载体 冲突} |
查看无线连接状态
ESSID参数为off显然还没有链接无线网络
root@raspberrypi:~# iwconfig
wlan0 IEEE 802.11 ESSID:off/any
Mode:Managed Access Point: Not-Associated Tx-Power=31 dBm
Retry short limit:7 RTS thr:off Fragment thr:off
Encryption key:off
Power Management:on
lo no wireless extensions.
eth0 no wireless extensions.查找无线网络
列出能够搜索到的全部无线网络
root@raspberrypi:~# iwlist wlan0 scan
wlan0 Scan completed :
Cell 01 - Address: A8:57:4E:86:7B:7E
Channel:1
Frequency:2.412 GHz (Channel 1)
Quality=43/70 Signal level=-67 dBm
Encryption key:on
ESSID:"TP-LINK_867"
Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 11 Mb/s; 6 Mb/s
9 Mb/s; 12 Mb/s; 18 Mb/s
Bit Rates:24 Mb/s; 36 Mb/s; 48 Mb/s; 54 Mb/s
Mode:Master
Extra:tsf=0000000000000000
Extra: Last beacon: 80ms ago
IE: Unknown: 000B54502D4C494E4B5F383637
IE: Unknown: 010882848B960C121824
IE: Unknown: 030101
IE: Unknown: 2A0100
IE: Unknown: 32043048606C
IE: Unknown: 2D1A6E1003FFFF000000000000000000000000000000000000000000
IE: Unknown: 3D1601050200000000000000000000000000000000000000
IE: IEEE 802.11i/WPA2 Version 1
Group Cipher : CCMP
Pairwise Ciphers (1) : CCMP
Authentication Suites (1) : PSK
IE: WPA Version 1
Group Cipher : CCMP
Pairwise Ciphers (1) : CCMP
Authentication Suites (1) : PSK
IE: Unknown: DD180050F2020101000003A4000027A4000042435E0062322F00
IE: Unknown: DD05000AEB0100
IE: Unknown: DD8E0050F204104A0001101044000102103B0001031047001000000000000010000000A8574E867B7E1021000754502D4C494E4B10230009544C2D57523834324E10240003342E3010420007312E312E312E331054000800060050F204000110110018576972656C657373204E20526F757465722057523834324E100800022288103C0001011049000600372A000120配置wifi信息
root@raspberrypi:~# vim /etc/wpa_supplicant/wpa_supplicant.conf 在配置文件中增加无线wifi的配置
...
network={
ssid="Xiaomi_F636"
psk="imlichao"
} 重启系统
重启系统后我们可以看到无线网卡已经启用并连接到了wifi。
root@raspberrypi:/home/imlichao# ifconfig
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.31.159 netmask 255.255.255.0 broadcast 192.168.31.255
inet6 fe80::a579:e25:d60e:838a prefixlen 64 scopeid 0x20<link>
ether b8:27:eb:08:b2:02 txqueuelen 1000 (Ethernet)
RX packets 895 bytes 48460 (47.3 KiB)
RX errors 0 dropped 1 overruns 0 frame 0
TX packets 91 bytes 13742 (13.4 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
inet6 ::1 prefixlen 128 scopeid 0x10<host>
loop txqueuelen 1000 (Local Loopback)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
wlan0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.31.134 netmask 255.255.255.0 broadcast 192.168.31.255
inet6 fe80::36eb:7046:a7fb:ddb3 prefixlen 64 scopeid 0x20<link>
ether b8:27:eb:5d:e7:57 txqueuelen 1000 (Ethernet)
RX packets 69 bytes 8121 (7.9 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 36 bytes 6014 (5.8 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0root@raspberrypi:/home/imlichao# iwconfig
wlan0 IEEE 802.11 ESSID:"Xiaomi_F636"
Mode:Managed Frequency:2.412 GHz Access Point: 64:09:80:12:F6:37
Bit Rate=24 Mb/s Tx-Power=31 dBm
Retry short limit:7 RTS thr:off Fragment thr:off
Encryption key:off
Power Management:on
Link Quality=55/70 Signal level=-55 dBm
Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:0 Invalid misc:0 Missed beacon:0
lo no wireless extensions.
eth0 no wireless extensions.