How do I bring up my wireless network at boot?

Question

I am running Ubuntu Server 12.04. I have a wireless USB card. When I begin the boot process I see:

Waiting for network configuration

It turns out that the network never comes up. But once I get to the command line, if I type: ifup wlan0, then I have network access. My /etc/network/interfaces looks like this:

# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
auto wlan0
iface wlan0 inet dhcp
wpa-ssid xxxxxxx
wpa-psk xxxxxxxx

Looking in my network-interface-wlan0.log shows:

Failed to connect to wpa_supplicant - wpa_ctrl_open: Read-only file system
Failed to bring up wlan0.
Failed to connect to wpa_supplicant - wpa_ctrl_open: Read-only file system
ifdown: interface wlan0 not configured

I've looked at other askubuntu.com questions similar to this, but they don't seem to apply.

How can I get my system to network wirelessly at boot?

Additional information:

I did some poking around. Basically once I login I need to do a:

ifdown wlan0

because I think that ip thinks that is is up, but in /var/run/network the only thing that is 'up' is ifup.lo. Then I do a

'ifup -a'

and then everything works.

pl1nk · Accepted Answer · 2012-05-31T01:05:01.870

12

Failed to connect to wpa_supplicant - wpa_ctrl_open: Read-only file system

According to your log you 'll need to use wpa_supplicant.

So add something similar to this:

auto wlan0
iface wlan0 inet dhcp
wpa-conf /etc/wpa_supplicant.conf

Contents of /etc/wpa_supplicant.conf :

network={
        ssid="ADD-YOUR-SSID-HERE"
        proto=RSN
        key_mgmt=WPA-PSK
        pairwise=CCMP TKIP
        group=CCMP TKIP
        psk="ADD-YOUR-WPA-PASSWORD-HERE"
}

edited May 31 '12 at 01:05

answered May 30 '12 at 08:36

pl1nk

6,399

What do we add it to? – Jason Kelley May 21 '20 at 17:38

score 1 · Answer 2 · edited Oct 20 '13 at 08:34

1

You can add ifup wlan0 to your /etc/rc.local file. Add the command ifup wlan0 before the exit 0. Also add the command ifdown wlan0 before the ifup wlan0 like so:

...
ifdown wlan0
ifup wlan0

exit 0

For some reason when Ubuntu starts, it thinks that wlan0 is up. So you have to shut it down and have it back up again.

edited Oct 20 '13 at 08:34

con-f-use

18,813

answered May 30 '12 at 05:15

Manula Waidyanatha

8,555

This didn't work. I don't think this is happening because ifup isn't be called. I think there's something else wonky going on with the networking system. – Son of the Wai-Pan May 30 '12 at 05:52
Hi, ifup wlan0 should be above the 'exit 0' line. Thanks @Piyush Kumar for mentioning – Manula Waidyanatha May 30 '12 at 06:57

score 1 · Answer 3 · answered Jun 05 '17 at 18:21

Connecting to WPA-PSK and WPA2-PSK (Aka "WPA Personal" and "WPA2 Personal" respectively)

Run:

$ wpa_passphrase myssid my_very_secret_passphrase

Copy the value of "psk=" from the output above.

Open /etc/network/interfaces in a text editor :

$ sudo sensible-editor /etc/network/interfaces

Define appropriate stanzas for your wireless interface, along with the SSID and PSK HASH. For example :
```
auto wlan0
face wlan0 inet dhcp
   wpa-ssid <myssid>
   wpa-psk <ccb290fd4fe6b22935cbae3144..>
```
Finally run:
```
$ sudo ifup wlan0
```

Note: Some answers seems to suggest configuring a separate wpa_supplicant.conf. But it is only required for WPA-EAP, EAP-TLS networks.

How can I get my system to network wirelessly at boot?

The auto stanza does bring up the interface at system startup.

score 0 · Answer 4 · edited Oct 05 '12 at 11:00

I also encounter such a problem.

I noticed that someone said, delete the text about primary network interface, with first 2 lines remaining.

It works, but no network is connected.

Then I write the text of primary network interface back into the interfaces file and reboot.

It's surprising to find not only no hints "waiting for network configuration" occur, but I could connect to the internet.

I don't know whether it is useful for any others.

score 0 · Answer 5 · edited Mar 25 '13 at 22:08

The reason for this is that the filesystem is read-only at boot. At this point only static settings work because udev raises network hotplug signal before the filesystem is ready.

The solution is to change the /etc/init/network-interface.conf file in this line:

"ifup --allow auto ..." to
"ifup --allow=hotplug ...".

You will have to mark you hotplug PCMCI and USB network adapters as "hotplug" in /etc/network/interfaces for them to continue to work, and you should plug them in after boot, not before.

How do I bring up my wireless network at boot?

5 Answers5

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