Wireless Roaming

Benedek Frank wrote:
> Is there a tool I can use for wireless roaming? I would need one I can
> somehow manage, as strongest signal almost never applies to me. I use
> in all my networks WEP with 128bit encryption, and Shared mode.
Well, waproamd was the weapon of choice when the world only used WEP.
Since you're only using WEP at this point, you could still use it....
but wpa_supplicant will also do what you want, but it's a bit
non-trivial to set up. It goes like this:

In your /etc/networking/interfaces, you put a section that looks like:
> auto ath0
> iface ath0 inet manual
> wpa-driver wext
> wpa-roam /etc/wpa_supplicant.conf
>
> # A config for wpa_supplicant to call. This just grabs any old address
> iface generic_dhcp inet dhcp
>
> # A config for wpa_supplicant to call. Special stuff for when you're
> at home
> iface home_wireless inet static
> address 192.168.1.12
> gateway 192.168.1.1
> post-up /some/script/that/connects/to/something/at/home
> pre-down /some/other/script/to/disconnect/from/home
The first section launches a wpa_supplicant to manage ath0 and scan for
AP's. When it finds some, it sees if any profiles in wpa_supplicant.conf
(below) match any that it found. It selects one and then, depending upon
the "id_str" in the section, calls the corresponding config in
/etc/network/interfaces.

In this case, there are two "pseudo" interfaces: generic_dhcp that just
grabs any dhcp address and doesn't do anything else, and there's a
"home_wireless" which uses a static address and also runs some scripts
to connect/disconnect from something (like, a network drive or something).

Now, /etc/wpa_supplicant.conf would look something like this (I've
clipped out some of the stuff at the top of mine... so this isn't
complete. Use your existing sample wpa_supplicant.conf as a starting point.
> network={
> ssid="SomeWPA"
> proto=WPA
> key_mgmt=WPA-PSK
> psk="MyWPAKey"
> auth_alg=OPEN
> priority=5
> id_str="home_wireless"
> }
>
> network={
> ssid="SomeWEP"
> auth_alg=SHARED
> key_mgmt=NONE
> wep_key0=12345678901234567890123456
> wep_tx_keyidx=0
> priority=6
> id_str="generic_dhcp"
> }
>
> ### Associate with any open access point
> network={
> ssid=""
> key_mgmt=NONE
> priority=4
> id_str="generic_dhcp"
> }
Here, I've specified three AP's. The last one is actually "any" access
point. What keeps wpa_supplicant from selecting it over the others is
NOT the order in which they appear, it's the "priority" line in each
one. wpa_supplicant will find all of the sections that match an AP that
it can see and then choose the one with the highest priority. Once it
does this, it looks at "id_str" to know which pseudo interface in
/etc/network/interfaces to invoke.

Hope this helps.

- Joe

>>>>> "Benedek" == Benedek Frank writes:

Benedek> Hi I have a Madwifi based card, and it works like a charm. I
Benedek> have 2 wifi networks I need to connect daily, both at home,
Benedek> and a 3^rd one at work which I need to use weekly few times.

http://manual.sidux.com/en/internet-connecting-wpa-en.htm

I found the above howto very useful in the situation that you are using.

Good luck.

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