wlan0 does not assign an IP addres if eth0 aldready has one

mr.simo · 07-25-2014, 06:37 AM

Hello,

I am facing with a problem I don't know how to solve.

In my device, let's call it C1, I have the following situation: eth0 and wlan0 interfaces can both have an IP address.

wlan0 works in Ad-Hoc mode, it has its own ESSID "MY_WLAN".

From an another computer, let's call it C2, when I try to connect to C1 through "MY_WLAN" network, if in C1 the eth0 has IP addres, wlan0 does not assign any IP address.

I am using udhcpd for wlan0 dhcp configuration.

I am not using network managaer.

This is my /etc/network/interface:

Code:

iface wlan0 inet dhcp
      pre-up wpa_supplicant -Dwext -iwlan0 -c/etc/wpa_supplicant/wpa_supplicant.conf -B
      post-up /usr/bin/confwifi.sh; udhcpd /etc/udhcpcd.conf;

iface gw inet dhcp
iface default inet dhcp
iface adhoc inet static

        address 192.168.2.2
        netmask 255.255.255.0

        network 192.168.0.0
        broadcast 192.168.0.255
        gateway 192.168.0.1


#auto eth0
allow-hotplug eth0
iface eth0 inet manual
post-up /usr/bin/confeth.sh

/usr/bin/confwifi.sh is just an ifconfig and an IP address, and it can change depending if I want to connect wlan to another router as Managed mode.

And this is my /etc/udhcpd.conf file

Code:

#start address
start           192.168.2.3

#end address
end             192.168.2.254

option dns 192.168.2.2
option subnet 255.255.255.0
option router 192.168.2.2

#interface to listen on
interface	wlan0

#maximum number of leases
max_leases	64

Thank you for your help.
Simon

SIG_SEGV · 07-25-2014, 08:03 AM

Try running dhclient in C1.... May be its not runnning currently

Or else release eth0 from dhclient...and then start dhclient back

Follow these cmds:

dhclient -r eth0
dhclient -v eth0

Also chck wth wireshark wheter dhcp pkts are captured at C1 LAN interface...

mr.simo · 07-28-2014, 04:03 AM

Hello SIG_SEGV,

Thank you for your reply.

I finally solved adding running again udhcpd after configuring eth0.

Code:

allow-hotplug eth0
iface eth0 inet dhcp
post-up /usr/bin/confeth.sh; killall udhcpd; udhcpd /etc/udhcpcd.conf;

It is solved now.