Re: Connection sharing

[Dan Williams <dcbw redhat com>]

On Thu, 2008-12-04 at 21:12 -0800, Bill Moseley wrote:
> I'm running Ubuntu 8.10 on a Thinkpad T60p w/ Atheros wireless.

madwifi or ath5k?  Only ath5k is supported, because madwifi isn't in the
upstream kernel.  NetworkManager only supports drivers that are shipped
in the official Linux kernel.  Since we cannot fix binary drivers, and
out-of-tree drivers are of questionable interoperability and quality,
they are not supported.

> Can someone point me to docs on sharing my connection with my
> wireless card when I'm on my wired LAN?
> 
> This video made it look easy:
> 
> http://www.redhatmagazine.com/2008/10/16/video-fedora-10-connection-sharing/
> 
> But when I select "Create New Wireless Network..." from the nm-applet
> menu the applet just says I've connected to my existing wireless
> network.  And with other computers I do not see any new network.

Is there a checkbox next to the wifi network you just created?  The icon
will show your *primary* internet connection, i.e. the one you are
sharing.  But the menu will also indicate the connection which is
sharing your primary connection.

> I suspect I need a bit of guidance.
> 
> I'm not quite sure I understand how it's suppose to work, really.
> Should my wireless card act as an AP and my existing dhcpd server
> provide IPs?  Or would my laptop perform NAT and share its IP address?
> And would I then need to setup dhcpd on the laptop?

The sharing capability requires dnsmasq-base (on Ubuntu).  If you
install that, when you "create new wireless network", it will create an
Ad-Hoc wifi connection and will start dnsmasq as a forwarding nameserver
and DHCP server on that adhoc network.  Other computers that connect to
that adhoc network will then be able to get a DHCP address.

While NetworkManager should be punching holes through the firewall to
allow the DHCP and DNS traffic for the sharing connection, you might try
to stop the 'iptables' service before starting connection sharing and
see if that makes a difference.

*however*, since you state that other computers cannot see the newly
created adhoc sharing network, this either indicates that you don't have
dnsmasq installed, or it indicates driver problems.  I had to fix quite
a few upstream drivers along the way to get adhoc networking to work
correctly, and fix wpa_supplicant in a few cases.  These changes are in
released kernels (2.6.27 and later) and also in the latest
wpa_supplicant releases (0.6.5 and later).

Dan