How to configure wireless network interface using CLI in Fedora Server

I wanted to use my wireless network adapter on Fedora Server (version 29). Even though there are ways configure it graphically on Fedora Server, I wanted to configure it using only CLI with minimum steps.

When I plugged the adapter to my server, it was shown as wlp0s21f0u4,

ip a command output,

wlp0s21f0u4: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc mq state DOWN group default qlen 1000

Therefore I chose wlp0s21f0u4 as my connection name.

Here are the steps I followed,

1. Create a network configuration file in /etc/sysconfig/network-scripts directory. File name: ifcfg-wlp0s21f0u4 (i.e. ifcfg-<connection name>)

Content of the file is,

[root@localhost network-scripts]# cat ifcfg-wlp0s21f0u4
TYPE=Wireless
BOOTPROTO=dhcp
DEFROUTE=yes
IPV4_FAILURE_FATAL=no
IPV6INIT=yes
IPV6_AUTOCONF=no
NAME=wlp0s21f0u4
ONBOOT=yes
DEVICE=wlp0s21f0u4
ESSID=bla
KEY_MGMT=WPA-PSK
MODE=Managed

The highlighted configuration parameters are important to establish a wireless connection. As you can see the SSID of my wifi network is bla and it uses WPA-PSK security.

2. Create another file to store the wireless key in the same directory. File name: keys-wlp0s21f0u4 (i.e. keys-<connection name>)

Content of the key file is,

[root@localhost network-scripts]# cat keys-wlp0s21f0u4
WPA_PSK=abc123

 As you can see the password is abc123 and it's stored as plain text.

3. Restart NetworkManager,

systemctl restart NetworkManager

4. After a couple of seconds, the network interface should be up,

ip a command output,

wlp0s21f0u4: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000

If you encounter issues, you can use journatctl for troubleshooting,

journalctl -xe -u NetworkManager

Modify Atheros AR9271 USB WiFi Adapter to add heat sinks

Today I received  Atheros AR9271 USB WiFi Adapter which I ordered from AliExpress. I ordered it after a thorough google search about Linux friendly WiFi adapters. As I expected it started to work on my Fedora desktop machine out of the box.

However I noticed that the adapter heats a little when I touched it after a few minutes. I was curious to see what caused the heat. So I decided to dissemble it. Disassembling the plastic enclosure of the adapter was not difficult. Sliding a piece of thin plastic or metal between the two pieces of the enclosure would open it.

The adapter actually uses a WiFi module. The chip was covered with a small metal sheet to handle the heat. The metal sheet was covered by a sticker which has the information of the module. (See the photo below)

WiFi Module

Hmm Nothing special. Oh wait is that a LED in the module? It is. There is a LED and it lights up when the adapter is turned on. It blinks when there is a data transfer. The enclosure does not have any hole above it so the light is not visible unless you disassemble it.

At that moment I decided to modify the USB enclosure. A simple small hole drilled through the top piece of the plastic enclosure would do the job. Hmm.. Why shouldn't you hack it further to add a heat sink?  Yes, It was a perfect crazy idea to ruin the enclosure. Also it may be a overkill to add a heat-sink for that small USB gadget. but I was already bored and looking for a job something like that. So I decided to modify the top piece of the enclosure to mount a heat-sink.

I didn't have a heat sink which matches with the size of the metal sheet. Nothing stops doing crazy things, Fortunately I had 2 small heat sinks which could cover the metal sheet.

First I drilled the top piece of the enclosure for the LED. Then I drilled the top piece multiple times using a small bit so that it could help to remove a rectangle piece from the enclosure. I used a small hand file to smooth the edges after that.

After I verified the rectangle space is good enough for the heat-sinks, I assembled the plastic enclosure. Then I mounted the two heat sinks on the metal sheet through the rectangular space I cut on the top of the enclosure.

The end result? Yes, it looks funny, but I like it.

Modified USB WiFi Adapter

The Modified Adapter in use