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From: Alfonso Fiore <alfonso.fiore@gmail.com>
Date: Fri, 3 Feb 2012 04:16:44 +0100
Message-ID: <CAO=xpBGLQazD30z3f+rs+MWuQgMSmhYzWyUFwunfcViRny9jnA@mail.gmail.com> (sfid-20120203_041719_583307_EE0C5AF8)
Subject: Re: how to setup a wireless bridge (wds) without iwpriv?
To: linux-wireless@vger.kernel.org
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Sender: linux-wireless-owner@vger.kernel.org

Hi Daniel,

thanks a lot, it worked like a charm! (not true, please read till the end)

A recap for my memory and for others looking to achieve the same thing
(feel free to correct any mistakes).

As far as I saw, the PC won't work with DHCP, so manually set an IP in
the right range.
This is my topology:
(ISP wireless router - 192.168.100.254) <---wireless---> (ALIX setup
as bridge) <---wired---> (PC - 192.168.100.100)

remember to set both the IP and the DNS in the PC. The PC netmask is
not affected by the setup, so keep 255.255.255.0.

Then on the ALIX, use this /etc/network/interfaces:

auto lo
iface lo inet loopback
auto eth0
iface eth0 inet static
        address 0.0.0.0
        netmask 255.255.255.255
auto wlan0
iface wlan0 inet dhcp
        wpa-driver wext
        wpa-ssid <<Your_AP_SSID_Here>>
        wpa-psk <<cleartext_password>>
        wpa-key-mgmt WPA-PSK
        wpa-pairwise TKIP
        wpa-group CCMP TKIP
        wpa-proto RSN
        wireless-mode Managed
        post-up route del -net 192.168.100.0 netmask 255.255.255.0
        post-up route add -net 192.168.100.128 netmask 255.255.255.128 dev wlan0
        post-up route add -net 192.168.100.0 netmask 255.255.255.0 dev eth0

then add to your /etc/rc.local:

echo 1 > /proc/sys/net/ipv4/conf/eth0/proxy_arp
echo 1 > /proc/sys/net/ipv4/conf/wlan0/proxy_arp
echo 1 > /proc/sys/net/ipv4/ip_forward

and you are good to go!

Ok this is just plain silly now. I did all the tests and the PC was
running perfect. Way faster than I expected (12Mbit/sec with
speedtest.net). I rebooted the ALIX to test the config files and it
worked. Then I disconnected and moved the ALIX box close to the PC,
disconnected "half" of the cables between ALIX and the PC (for the
test I was using 2 cables connected with an RJ45 extender) and run the
test again. It's super slow (speedtest.net can't measure it). I
rebooted the PC, the DSL router and the ALIX several times. I moved
again the ALIX near my laptop and I got 4Mbit/sec from the PC (but not
12Mbit). The router is less than 3 meters away, no walls in between.
During the tests the ALIX was 1 meter from the DSL router.
I also tried to switch off the TV (the only source of electromagnetic
pollution I can think of) but it doesn't change results.
I tried to put the ALIX on the PC case and on a wood table (thinking
about some problem due to the metal PC case).
I feel cursed.

thanks again,
alfonso

On Thu, Feb 2, 2012 at 8:29 PM, Daniel Gl?ckner <daniel-gl@gmx.net> wrote:
> Hi Alfonso,
>
> On Thu, Feb 02, 2012 at 07:22:30PM +0100, Alfonso Fiore wrote:
>> Since wireless on my PC doesn't work properly, I'd like to create a
>> wireless bridge to allow a PC to get an IP address from the wireless
>> network without NAT.
>>
>> (ISP wireless router - 192.168.1.1) <---wireless---> (ALIX setup as
>> bridge) <---wired---> (PC - 192.168.1.x)
>
> I use proxy ARP to achieve this with WPA:
>
> route add -net 192.168.1.0/25 dev wlan0
> route add -net 192.168.1.128/25 dev eth0
> echo 1 >/proc/sys/net/ipv4/conf/wlan0/proxy_arp
> echo 1 >/proc/sys/net/ipv4/conf/eth0/proxy_arp
> echo 1 >/proc/sys/net/ipv4/ip_forward
>
> But it only works if you know beforehand on which interface your ALIX
> will see an IP address. You could run the DHCP server on your ALIX to
> make it more deterministic.
>
> ?Daniel