[mythtv-users] HowTo avoid password nagging

[Karl Reichert]

> On Sun, 2007-12-09 at 19:43 +0000, Nicolas Will wrote:
> > hmm...
> > 
> > The problem with that statement is that network manager does
> > absolutely
> > no WPA on its own. It relies entirely on wpasupplicant for this.
> > 
> > So, if network manager works, wpasupplicant works.
> > Then /etc/network/interfaces should work.
> 
> Let me rephrase this... only in a quite longer monologue.
> 
> 
> 
> NetworkManager is just a GUI. A clever piece of GUI, but a GUI
> nevertheless.
> 
> NetworkManager will probe the network driver (a kernel module) through a
> standard interface in order to access it (wext). It will get all sort of
> info about the available networks, like ESSID names, BSSIDs, Crypto
> types. It displays that list to you in the dropdown menu.
> 
> Once you select a network in that menu, NetworkManager will generate a
> wpasupplicant config and pass it to wpasupplicant, wait for proper
> authentication to happen (done by wpasupplicant through wext too) and
> the cryptography to be setup (done by wpasupplicant through wext too),
> then run a dhcp request for an IP address.
> 
> So, NetworkManager is just a graphical remote control for wext and
> wpasupllicant.
> 
> NetworkManager is not a wireless device driver, it never talks directly
> to device drivers. It does not do any authentication or cryptography by
> itself. It uses wext and wpasupplicant.
> 
> wpasupplicant is not a device driver, it never talks directly to device
> drivers. It uses wext.
> 
> This is why I am reaching the conclusion that if you can connect to you
> network using NetworkManager, then wpasupplicant must be working.
> 
> As an aside... I you go to the NetworkManager dev list and complain
> about it not working, the first thing you will be asked is about making
> it work first manually using only wpasupplicant, and then provide the
> wpasupplicant conf file you used.
> 
> 
> 
> Now, about what I was advising you to use.
> 
> I gave you a link to a document on how to configure
> the /etc/network/interfaces file.
> 
> /usr/share/doc/wpasupplicant/README.modes.gz
> 
> This file is the basic Debian way of configuring network. NetworkManager
> came later and had to adapt to it (needed to be adapted to it, really).
> 
> This file is in fact a configuration file for a bunch of scripts that
> are run when the network is starting.
> 
> All the configuration items starting with wpa- will in fact be used in
> order to generate a wpasupplicant configuration, which will be then used
> by wpasupplicant itself.
> 
> So you can consider /etc/network/interfaces to be a manual and
> text-based NetworkManager, only less automated.
> 
> /etc/network/interfaces works the same way, except that it never probes
> anything by itself and needs a minimum information beforehand. It never
> talks to the kernel driver, it just uses wpasupplicant.
> 
> /etc/network/interfaces will have the pre-shared key, it does not need
> any keyring manager.
> 
> 
> 
> Moreover, the Ubuntu implementation of NetworkManager scans for
> interfaces configured in /etc/network/interfaces when it starts. If any
> interface is manually configured there, it will leave it as it is and
> not manage it in any way, thus avoiding a conflict of interests.
> 
> 
> 
> <soap box>
> As a gratuitous and pedantic remark I will say
> that /etc/network/interfaces is the "only one true Debian way" of
> configuring the network on a Debian/Ubuntu system. NetworkManager is
> late-coming click'O'matic that still has issues.
> 
> Don't get me wrong, I'm a big fan of NetworkManager on my laptops, I
> just think that it should be avoided on fixed systems, especially
> server-like devices, like MythTV systems tend to be.
> </soap box>
> 
> 
> 
> 
> In conclusion...
> 
> If NetworkManager works, then wpasupplicant works.
> 
> If wpasupplicant works, then /etc/network/interfaces should work.
> 
> The device driver is irrelevant.
> 
> 
> 
> Those were my slightly inflated 2 cents, and I am hoping they will help.
> 
> Nico
> 
Thanks to your very detailed explanations. I didn't had any experience with wireless network and linux before, so I did not know, that I could configure WLAN over /etc/network/interfaces. I was trying with wpa_supplicant.conf and network manager, which is indeed unnecessary for me, as I don't need any roaming.

So, what I did, is to configure WLAN via /etc/network/interfaces and when I start mythbuntu, network manager doesn't asks anymore for a password, as it doesn't touch the interface, which is already configured via /etc/network/interfaces.

One little problem is left:
I have to perform 'ifup wlan0' after startup, and my WLAN is connecting to the AP without any problems.
If I put 'auto wlan0' into /etc/network/interfaces, it's not working. 'ifconfig' shows me an additional wmaster0 interface and iwconfig shows, that my wlan card is not connected to any AP.


Any ideas, how to automatically startup wlan0 at boot time? I thought about a shell script, what do you say?

Thanks in advance!
Karl
-- 
von Karl Reichert

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