Ubuntu16.04 the wireless network card cannot connect to the network normally,

Ubuntu16.04 the wireless network card cannot connect to the network normally,

Background: The wireless network adapter can access the Internet normally when it is connected for the first time.

Version: Ubuntu 16.04

I. Analysis:

1. Use the ifconfig command to find that the wireless network card is not displayed. This indicates that the wireless network card is disabled. The output is as follows:

Jello @ jello :~ $ Ifconfig

Eth0 Link encap: Ethernet hardware address 16: 03: 71: 93: 64: 22
Inet address: 192.168.100.3 broadcast: 192.168.100.255 mask: 255.255.255.0
Inet6 address: fe80: 1a03: 73ff: fe92: 632e/64 Scope: Link
Up broadcast running multicast mtu: 1500 hops: 1
Received data packet: 295308 error: 0 discard: 0 overload: 0 frames: 0
Send data packets: 208860 error: 1 discard: 0 overload: 0 carrier: 0
Collision: 0 sending queue length: 1000
Received byte: 394951279 (394.9 MB) sent byte: 19510963 (19.5 MB)

Lo Link encap: local loopback
Inet address: 127.0.0.1 mask: 255.0.0.0
Inet6 address: 1/128 Scope: Host
Up loopback running mtu: 65536 hops: 1
Received data packet: 943526 error: 0 discard: 0 overload: 0 frames: 0
Send data packets: 943526 error: 0 discard: 0 overload: 0 carrier: 0
Collision: 0 sending queue length: 1
Received byte: 464924375 (464.9 MB) sent byte: 464924375 (464.9 MB)

2. Use the lshw command to output the following information (only information about the wireless network adapter is attached:

Jello @ jello :~ $ Lshw

*-Network DISABLED
Description: Wireless interface
Physical id: 2
Logical name: wlan0 1
Serial: 92: 31: e3: 4a: 75: f2
Capabilities: ethernet physical wireless
Configuration: broadcast = yes driver = brcmsmac driverversion = 4.1.0-78-generic firmware = 102.304 ip = 192.168.100.131 link = no multicast = yes wireless = IEEE 802.11bgn

The Line "*-network DISABLED" at indicates that the wireless network card is DISABLED on the hardware.

3. When the hardware switch is turned on, but failed many times, the output information of rfkill is used to judge:

Jello @ jello :~ $ Sudo rfkill list all
[Sudo] jello password:
0: phy0: Wireless LAN
Soft blocked: no
Hard blocked: yes

From the line "Hard blocked: yes", we can see that the wireless network card is block on the hardware.

4. Check whether the driver of the wireless network card is correctly installed.

2. Install the wireless NIC Driver:

1. Uninstall the previously installed wireless NIC Driver (if you have installed the driver before, otherwise ignore it ):

Sudo apt-get purge firmware-b43-installer

sudo apt-get purge bcmwl-kernel-source

2. Obtain the PCI. ID of the wireless network card (the author's brand of the wireless network card is broadcom, so the specified vendor code is 14e4)

Jello @ jello $ lspci-nn-d 14e4:
. 0 Network controller [0280]: Broadcom Corporation BCM4313 802.11bgn Wireless Network Adapter [14e4: 4727] (rev 01)

The key information obtained from the above information is: [14e4: 4727] (rev 01)

-Nn option is used to display only devices corresponding to the specified manufacturer code.

The-d option displays both the vendor code and device code, and numbers and names.

3. Update the PCI. IDs list of ubuntu:

3.1 sudo apt-get update (update the software package index first)

3.2 sudo update-pciids (if there is no response, it will be disconnected), directly replace the original/usr/share/misc/pci. ids file, the command is as follows:

Cd/usr/share/misc/

Sudo mv pci. ids pci. ids. orig

Then download the latest pic.ids file from http://pci-ids.ucw.cz/

The downloaded pci. copy the ids file to the/usr/share/misc/directory (because the current hardware of the wireless network card is not very new, the information of the wireless network card is in the original pci. ids files exist, so pci is not updated manually. ids file)

4. Install the corresponding wireless NIC Driver and obtain the software package name of the driver from the following table.

PCI. ID 16.04 LTS 17.10 + small 14e4: 0576 Special Case #1 UNKNOWN 14e4: 4301 firmware-b43-installer firmware-b43-installer 14e4: 4306 firmware-b43-installer 14e4: 4306 rev 02 firmware-b43-installer 14e4: 4306 rev 03 firmware-b43-installer firmware-b43-installer 14e4: 4307 firmware-b43-installer firmware-b43-installer 14e4: 4311 firmware-b43-installer firmware-b43-installer 14e4: 4311 rev 01 firmware-b43-installer 14e4: 4312 firmware-b43-installer firmware-b43-installer 14e4: 4313 firmware-b43-installer firmware-b43-installer 14e4: 4315 firmware-b43-installer firmware-b43-installer 14e4: 4315 rev 01 firmware-b43-installer firmware-b43-installer: 4318 firmware-b43-installer firmware-b43-installer 14e4: 4318 rev 02 firmware-b43-installer firmware-b43-installer 14e4: 4319 firmware-b43-installer 14e4: 4320 rev 02 firmware-b43-installer 14e4: 4320 rev 03 firmware-b43-installer 14e4: 4321 firmware-b43-installer firmware-b43-installer 14e4: 4324 firmware-b43-installer firmware-b43-installer 14e4: 4325 firmware-b43-installer firmware-b43-installer 14e4: 4328 firmware-b43-installer 14e4: 4329 bcmwl-kernel-source 14e4: 432a bcmwl-kernel-source 14e4: 432b bcmwl-kernel-source 14e4: 432c bcmwl-kernel-source 14e4: 432d bcmwl-kernel-source 14e4: 4331 firmware-b43-installer firmware-b43-installer 14e4: 4335 firmware-b43-installer firmware-b43-installer 14e4: 4350 firmware-b43-installer 14e4: 4353 Special Case #1 UNKNOWN 14e4: 4353 rev 01 Special Case #1 UNKNOWN 14e4: 4357 Special Case #1 UNKNOWN 14e4: 4358 bcmwl-kernel-source bcmwl-kernel-source14e4: 4359 bcmwl-kernel-source 14e4: 4360 bcmwl-kernel-source 14e4: 4365 bcmwl-kernel-source 14e4: 4365 rev 01 bcmwl-kernel-source 14e4: 43a0 bcmwl-kernel-source bcmwl-kernel-source14e4: 43ae rev 02 UNKNOWN 14e4: 43b1 bcmwl-kernel-source 14e4: 43b1 rev 03 bcmwl-kernel-source 14e4: 43c3 rev 04 UNKNOWN Special Case #2 14e4: 4727 bcmwl-kernel-source 14e4: 4727 rev 01 bcmwl-kernel-source 14e4: a962 firmware-b43-installer firmware-b43-installer forever ------------------------------------------------------------------------------------
4.1 from the preceding table, we can see that bcmwl-kernel-source corresponds to 14e4: 4727 rev 01. Therefore, the installation command is as follows:
Sudo apt-get install bcmwl-kernel-source
4.2 restart