No subject

[Vincent Chin]

Ripped from

http://www.hpl.hp.com/personal/Jean_Tourrilhes/Linux/Linux.Wireless.usage.html

" 11 Access Points, Home Gateways and Ethernet bridging
Most Access Points act as a MAC level bridge, allowing the Wireless LAN to 
be a natural extension of a wired network. They are deployed in a cellular 
fashion, and provide extended security, management and roaming.
On the other hand, the Home Gateways allow a single cell to be connected to 
a WAN, like a modem, a cable modem or a DSL access. The set of features is 
quite different, and they offer NAT/masquerading and PPP configuration.

The conventional Ethernet bridging method (promiscuous sniffing) doesn't 
work with most wireless LAN standard, because of the header encapsulation 
and the interactions with link layer retransmissions. In other word, most 
often, when you use a software bridge on a wireless LAN (such as the Linux 
bridge on a 802.11 card), it doesn't work (moreover, quite often promiscuous 
is broken as well). "

[[ What the?? What is he talking about?? Aren't we all using Linux to bridge 
our networks? ]]

" The driver could work around this restriction by creating its own MAC 
headers (802.11 headers instead of 802.3, and putting the right bits in the 
right place), but in fact most vendors don't provide the specification on 
how to this with their hardware (when they don't explicitely prevent it in 
hardware, to force you to buy their Access Points).

In other words, don't expect to use your Linux PC as a wireless bridge or 
wireless Access Points with most products out there, and forget about 
turning it into an Access Point. Of course, there is some exceptions. "

[[ Is this true? ]]


" The workaround is to set the wireless LAN in ad-hoc mode and to use other 
methods, such as routing, masquerading, IP bridging, ARP proxying... "


[[ Yes, I am in a process of building a wireless-lan <-> wired-lan bridge. 
But I don't understand what this guy is talking about. Anyone?


Vince. ]]




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