[ubuntu-nz] Wireless mysteries

[Bruce Kingsbury]

2008/11/19 Johann Schoonees <johann at schoonees.org.nz>:
> Talking of wireless networking, I have a D-link DI-624S Wireless 108G
> Storage Router and a D-link DWL-G122 Wireless G USB Adapter:
>
> [1] I read in Thomas's "Beginning Ubuntu Linux" which is mostly based on
> Dapper that WPA is not yet well supported by Linux and WEP is strongly
> recommended.  I enabled WPA in my wireless router before I read that and
> things eventually started working after an annoying bout of logging in
> and out.  Is that advice still the case for Hardy?

For me it was as easy as 'select AP, enter passphrase'. And that was
right off the live CD, no drivers, no other network connection to
install them. For less well supported cards you might need to sort out
the drivers first.

> [2] When I select WPA authentication on my wireless router, it appears
> as "WPA Personal" in NM.  What's the "Personal" about?  Are there
> different flavours of WPA?

Yes, there's ordinary WPA (pre-shared key or "personal" mode) and EAP
(authenticated or "enterprise" mode) which requires an authentication
server.

>
> [3] I use Network Manager which appears to be the default with Hardy.
> What does "roaming mode" or "Roaming mode enabled" mean?  There's no
> mention in the NM Help documents of it.

Roaming mode means it will try to sort out a connection however it
can; connecting to any AP's you've used previously, with the keys
stored on your keyring and DHCP. AFAIK It'll only do this after you
log in though. If you configure it, that sets up an entry in
/etc/network/interfaces and it will try to bring up the interface at
boot time.

At least that's my understanding

> [4] If I uncheck the "roaming mode" checkbox, I get to set the wireless
> network name, passphrase, DHCP, etc.  However, that removes the wireless
> connection and I can only get the relevant NM right-click menu items
> back by enabling "roaming" again.  Mine is a fixed desktop computer
> which only uses wireless LAN for convenience (the ADSL socket is far
> away and it's difficult to run new cables in my house).  It's not about
> to "roam" anywhere soon.  Why does disabling roaming mode also disable
> wireless networking?

Wireless networking is a little flakey in ubuntu. I just now set my
laptop to a properly configured wireless connection and it doesn't
come up either. sudo ifdown wlan0; sudo ifup wlan0 after the machine
is properly booted brings it up though. As a quick hack you could put
this as an @reboot entry in root's crontab. Or you could just leave it
on roaming mode if that works.

> [5] When I hover the mouse over the NM icon in the system tray, it says
> something like "Wireless network connection (69%)".  Again, no mention
> in the Help docs.  What does the percentage mean, and will the
> connection be slower when it's low?

signal strength.. and yes, it'll slow down when the signal is really weak.

I'd suggest
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