dhclient on boot after wpa_supplicant

**Keozon** · February 14th, 2011

Hello wonderful Ubuntu-gurus. I apologize if there's a solution to this somewhere on the forum, but I searched around on google for several hours before posting this, so I assure you, I'm not trying to waste your time.

Here's the deal. I have a file/print server running wpa_supplicant on interface wlan0 via ndiswrapper. Its wireless because the location I need the printer in is really inconvenient to have to run wires to, or I wouldn't have this problem.

The box is running ubuntu server 10.10, with only ndiswrapper and the associated utils and wpa_supplicant installed in addition to the default packages required for file/print/web serving. (there may be a few trivial packages like Vim that should have no effect whatsoever.)

Basically, wpa_supplicant associates fine with the AP, but I can't get any elegant way of getting a IP address with it, DHCP or static makes no difference. My current fix is my rc.local file has:

Code:

sleep 60
dhclient wlan0
return 0

which works, except that startup takes a minute longer than it should, and occasionally association takes longer than 60 seconds, which means it fails.

/etc/network/interfaces contains:

Code:

#This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
#iface eth0 inet dhcp

#Wireless Networking Devices
auto wlan0
iface wlan0 inet dhcp
        pre-up wpa_supplicant -Dwext -iwlan0 -c/home/server/wpa.conf
        post-down killall -q wpa_supplicant

wpa.conf contains

Code:

network={
        ssid="ACTIONTEC"
        #psk="CENSORED"
        psk=CENSORED
}

and finally, /etc/dhcp3/dhclient.conf

Code:

option rfc3442-classless-static-routes code 121 = array of unsigned integer 8;

send host-name "<hostname>";
#send dhcp-client-identifier 1:0:a0:24:ab:fb:9c;
#send dhcp-lease-time 3600;
#supersede domain-name "fugue.com home.vix.com";
#prepend domain-name-servers 127.0.0.1;
request subnet-mask, broadcast-address, time-offset, routers,
        domain-name, domain-name-servers, domain-search, host-name,
        netbios-name-servers, netbios-scope, interface-mtu,
        rfc3442-classless-static-routes, ntp-servers;
#require subnet-mask, domain-name-servers;
timeout 10;
retry 60;
#reboot 10;
#select-timeout 5;
initial-interval 2;

I have tried changed the interfaces file to static and listing the network info, as I don't need it to be dynamic, and it doesn't work at all. If I don't run dhclient manually (or with rc.local) netstat -r outputs nothing, and ifconfig lists only IPv6 address.

Any help with a more elegant solution would be wonderful.

**James78** · February 15th, 2011

Here's how I do mine (it's never failed me). If my instructions are not exact, just let me know and I'll try to fix them.

/etc/network/interfaces

Code:

...
# The primary network interface
auto wlan0
iface wlan0 inet static
	address 192.168.1.120
	netmask 255.255.255.0
	network 192.168.1.0
	broadcast 192.168.1.255
	gateway 192.168.1.1

Then..

Code:

sudo wpa_passphrase apname > /etc/wpa_supplicant.conf
<enter password>

/etc/rc.local

Code:

#!/bin/sh -e
#
# rc.local
#
# This script is executed at the end of each multiuser runlevel.
# Make sure that the script will "exit 0" on success or any other
# value on error.
#
# In order to enable or disable this script just change the execution
# bits.
#
# By default this script does nothing.

# start wpa_supplicant in background mode
wpa_supplicant -iwlan0 -c/etc/wpa_supplicant.conf -B
# start up dhclient
dhclient wlan0

exit 0

Extra reference (probably not much help though, basically the same thing I said above)
http://ubuntuforums.org/showpost.php...5&postcount=11

**LasTSuRvivoR** · March 4th, 2012

Thanks for the answer but is there a way to do this without asking for a static ip ?

**kevdog** · March 4th, 2012

See here it should be all you need:
http://ubuntuforums.org/showthread.php?t=202834

**vinaobraga** · August 31st, 2012

Hello Guys.

I'm trying to configure my wireless connection on my server but something weird is happening.
I have two cards on my server, one wired and another one wireless.
After set up all the setting of wpa_supplicant and execute the commands to connect, the wlan0 network get IP and connected on my AP.
But, when I log into my AP and ask to list all attached devices, I see the wlan0 card connected with the same MAC Address from the wired card. And if I unplug the network cabe from eth0, both connections goes down.

I will sent the steps that I followed with my configuration files to see if you can help me, please.

root@server:~# ifconfig
eth0 Link encap:Ethernet HWaddr 00:08:54:21:27:1f
inet addr:192.168.1.9 Bcast:192.168.1.255 Mask:255.255.255.0
inet6 addr: fe80::208:54ff:fe21:271f/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:1116 errors:0 dropped:0 overruns:0 frame:0
TX packets:517 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:106880 (106.8 KB) TX bytes:80933 (80.9 KB)
Interrupt:19 Base address:0x2c00

lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:16 errors:0 dropped:0 overruns:0 frame:0
TX packets:16 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:1524 (1.5 KB) TX bytes:1524 (1.5 KB)

wlan0 Link encap:Ethernet HWaddr 00:06:4f:70:f8:c8
inet addr:192.168.1.10 Bcast:192.168.1.255 Mask:255.255.255.0
inet6 addr: fe80::206:4fff:fe70:f8c8/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:130 errors:0 dropped:0 overruns:0 frame:0
TX packets:122 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:19857 (19.8 KB) TX bytes:21919 (21.9 KB)

root@server:~#

Follow the steps:

ifconfig wlan0 up
ifconfig
wpa_supplicant -Dwext -iwlan0 -c/etc/wpa_supplicant/wpa_supplicant.conf -B
ifconfig
ps aux | grep [w]pa
iwconfig wlan0
dhclient wlan0

root@server:~# cat /etc/wpa_supplicant/wpa_supplicant.conf
ctrl_interface=/var/run/wpa_supplicant
network={
ssid="AP-NOVO"
scan_ssid=1
proto=WPA
key_mgmt=WPA-PSK
#psk="REMOVED"
psk=REMOVED
}
root@server:~#

root@server:~# cat /etc/network/interfaces
# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
auto eth0
iface eth0 inet dhcp

#wireless
auto wlan0
iface wlan0 inet dhcp

Follow the output of the attached devices from router:

3 192.168.1.9 SERVER 00:08:54:21:27:1F
4 192.168.1.10 SERVER 00:08:54:21:27:1F

if you can see, the MAC is the same of the eth0.

What is wrong? I want to use only the wireless card..is it possible, right?

I'm running ubutu 12.04.

Thanks in advanced by any help.

**jcjveraa** · December 27th, 2012

Heya, I was having some issues stoo. My solution is exactly wat the first poster had, and just added -B to the pre-up line. I didn't change anything for the dhclient or rc.local. This was in 12.04 by the way.

The .conf file should of course point to the proper location.

So in /etc/network/interfaces I have

Code:

#Wireless Networking Devices
auto wlan0
iface wlan0 inet dhcp
        pre-up wpa_supplicant -Dwext -iwlan0 -c/etc/wpa_supplicant.conf -B
        post-down killall -q wpa_supplicant