How to connect to Wi-Fi network in Arch Linux?

Question

tl;dr After reading the Arch wiki articles on installation, wireless setup and WPA supplicant, trying the suggestions below and a host of forum threads, I'm unable to get either of the following cards to connect to my wireless network when booting the Arch Linux 2013-09-01 ISO:

• Edimax Technology Co., Ltd EW-7811Un 802.11n Wireless Adapter (ID 7392:7811)
• Realtek Semiconductor Corp. RTL8192CU 802.11n WLAN Adapter aka. Bolse® 300Mbps Wifi Wireless N USB Micro Mini Adapter (ID 0bda:8178)

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Approach 1 (default):

The default way of doing this is supposed to be just systemctl stop dhcpcd.service followed by wifi-menu. It finds the network:

[SSID] + wpa 10

After a timeout it reports that the connection failed. If I run wifi-menu a second time it doesn't ask for a password, but when finished it finally gives some debug hints:

Job for netctl@wlp0s29f7u5\x2dBTHub4\x2dGRK6.service failed. See 'systemctl status netctl@wlp0s29f7u5\x2dBTHub4\x2dGRK6.service' and 'journalctl -xn' for details.

The former reports that the service is "loaded" but not "active" (literally inactive (dead)). The latter says:

WPA association/authentication failed for interface 'wlp0s29f7u5'

Does this mean the key in /etc/netctl/wlp0s29f7u5-BTHub4-GRK6 is wrong? I can't tell when programs want the actual Wi-Fi password and when they want something like the psk value from wpa_passphrase (man 5 netctl.profile doesn't say, for example).

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Approach 2 (wpa_supplicant and wpa_passphrase as per deeraf and warl0ck's suggestions and the wiki page):

# echo 'ctrl_interface=/var/run/wpa_supplicant' > wifi.conf
# wpa_passphrase essid passphrase >> wifi.conf
# wpa_supplicant -B -i interface -c wifi.conf
Successfully initialized wpa_supplicant
# dhcpcd -A interface
[...]
timed out
exited

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I tried connecting with iw directly, but got some strange output:

# iw dev wlp0s26f7u5 connect [SSID]
command failed: Operation not supported (-95)

Answer 1

Did you setup your passphrase with wpa_passphrase? e.g

%> wpa_passphrase SSID passphrase
network={
        ssid="SSID"
        #psk="passphrase"
        psk=28964ba6ea8b8f3a0db1c4414b327da253d0af5d4f4adccec0f8abf5b05b10f8
}

Otherwise wpa_supplicant -B -i [wireless device] -c /etc/wpa_supplicant/cli.conf won't work at all

Answer 2

It seems like the main problem is the BT Home Hub version 4 which came with the Internet subscription. After disabling 5 GHz wireless, WPS, 802.11 n, automatic channel selection and setting security to WPA2 only, I'm now able to get a connection within seconds in both Ubuntu and Windows, and a very sketchy connection (as in, ~30 seconds connectivity every few minutes with wpa_supplicant) with an up-to-date Arch Linux.

Update: After using NetworkManager (nmcli dev wifi connect SSID password PASSWORD) I am getting what seems like a little more stability - it still drops out every few minutes or so.

Windows also does not always get a connection for several minutes, after which it seems stable.

(I also tried connecting an old ADSL router, not realising that it cannot understand a VDSL signal.)

Answer 3

wifi-menu should set up your passphrase for you. There shouldn't be a need to set it up manually. Check the configuration for wlp0s29f7u5 in /etc/conf.d/network-wireless@. Also check /etc/wpa_supplicant.conf to see if the information is correct.

Another thing, unless you are trying to set up a static address you shouldn't need to stop the dhcpcd service. If it is static then make sure you declare that in /etc/conf.d/network-wireless@

Finally provide and ip. 'dhcpcd wlp0s26f7u5' for dhcp

or for static do the following.

ip addr add "your ip"/24 dev wlp0s26f7u5 ip route add default via

EDIT

The file I was trying to refer to is in netctl. Here is mine:

[verdict@sparky ~]$ cat /etc/netctl/wlo1-ZombieNet 
Description='Automatically generated profile by wifi-menu'
Interface=wlo1
Connection=wireless
Security=wpa
ESSID=ZombieNet
IP=dhcp
Key=<my password>