[CLUE-Tech] More 802.11 Woes

[Nate Duehr]

On Sunday, Jan 18, 2004, at 20:13 America/Denver, Timothy C. Klein 
wrote:

> Hey again,
>
> So I recently posted about my Linksys WMP11 802.11b card that did work.
>
> Well, I decided to buy bridges, instead, and not futz with drivers. I
> like the features/speed/price of the D-Link DWL-2000AP. It supposedly
> can be a client, an AP, a p2p bridge, or a point-to-multipoint bridge.
> The latter is what I thought I wanted. It also can to WPA, and 2x 54
> Mbps if both ends are D-Link.
>
> Well, I got it, but I am unhappy, again.  Am I crazy in expecting the
> following scenario to work:
>
> Keats: Debian Linux, My office
> Usul: Debian, Wife's office
> Keatsap: DWL-2000AP
> Usulap: DWL-2000AP
> Dslap: DWL-2000AP, connected to Zoom DSL modem, phone line, living 
> room.
>
> I have it hooked up as:
>
> Keats --> Keatsap -->
>                      \
>                       \
>                        --> Dslap --> Zoom --> Internet
>                       /
>                      /
> Usul  --> Usulap  -->
>
> Zoom:    192.168.44.1
> Usul:    192.168.44.2
> Keats:   192.168.44.3
> Dslap:   192.168.44.4
> Keatsap: 192.168.44.5
> Usulap:  192.168.44.6
>
> The Dslap is configured in point-to-multipoint bridging. Usulap and
> Keatsap are configured in point-to-point bridging, and have the MAC
> address of Dslap.
>
> It works as far as getting Usul and Keats on the Internet.  However,
> Usul and Keats cannot see each other.  Am I crazy in expecting bridging
> to work that way?
>
> I actually tried it with Dslap as a Access Point, and the Keatsap and
> Usulap as Wireless clients, but that fails to work at all, which
> surprises me.  I am beginning to think that the D-Link firmware is just
> damn buggy, but I am no expert on how this technology functions, so I
> could be wrong.
>
> (No encryption of any kind is turned on, at this point.  I have also
> tried many, many iterations of feature toggling on the DWL-2000APs to
> try and straighten things out, to no avail).

Your network looks "similar" to mine here, but I'm using Linksys stuff.

Oh, my ASCII art stuff sucks though... so I won't even attempt it.  
However I have done exactly what you're attempting with the Linksys 
AP's and they work fine.  Multiple wireless AP's in "client" mode or 
bridging mode with nodes "behind" them on their ethernet ports, 
connecting to a central AP doing real wireless AP duties.

There is one major difference, however... in-between Dslap and Zoom on 
your diagram, I have a Linux box that is the firewall for all the 
private-side stuff.  All the internal boxes DHCP from it if they're not 
on statics for port-forwarding or whatever, and they all know it as 
their default router.  Since it knows what interfaces it's seen traffic 
from internal addresses come from, it's routing things "back in" 
through what in your network would be Dslap to the other machines.

Perhaps the Dslap box can't deal with routing between two bridged 
wireless segments internally but a machine beyond Dslap could handle 
routing for the entire internal network out to the outside world 
instead of letting Dslap and Zoom do it... just a possibility... also 
gives you a great place to tcpdump from to see what's going on when 
things are not happy.  ;-)

Right now my second wireless "leg" is non-existant -- I uninstalled it, 
but I have a number of regular wireless clients (the OSX machine, the 
laptop, the upstairs desktop PC, the printer/fax in the kitchen) that 
can all talk to everything else on the wireless and wired portions of 
the network.  I've not seen any problems with the Linksys gear not 
being able to do this, but I again have that central "router" in a 
Linux box which moves the job of routing pretty much completely out of 
the Linksys boxes and makes them just "transport".

(There's also a wired network and two switches... one that sits between 
the Cisco 678 (your "zoom") for machines that need public IP's, and 
another switch that sits behind the Linux firewall for machines that 
are hard-wired on the internal network.... the Linksys that would be 
Dslap in your diagram plugs into that "internal" switch.  Yeah, my home 
network is a bit out of control...)

--
Nate Duehr, nate at natetech.com