How to force a connection to go out of machine?

[James Knott]

James Knott wrote:
> Lennart Sorensen wrote:
>> On Thu, May 16, 2013 at 07:18:07PM -0400, James Knott wrote:
>>> >Well, with consumer level routers, the WiFi is generally bridged to
>>> >the Ethernet, so it's not going to make any difference. As for
>>> >allowing foreign addresses, as I mentioned, that's basic firewall
>>> >stuff and it would have to be a crappy firewall that allowed it.  In
>>> >short, the router portion should not pass any traffic from an
>>> >address that's not within it's configured subnet.  This is done to
>>> >prevent spoofing.  On the other hand, industrial level routers can
>>> >be configured to do that, with appropriate rules.
>> Actually many routers I have seen have the wlan software bridged to the
>> lan ports.
>>
>> In fact I am not sure I have ever seen one that wasn't done that way
>> given the AP has to control the wifi port a lot, which would perhaps be
>> harder if it was hardware bridged to the switch chip.
>
> There's a whole lot that goes on between WiFi and the Ethernet switch 
> part of those consumer routers.  Regardless, when all is said and 
> done, Wifi traffic appears on that switch as though it came in via 
> Ethernet.  It's the same thing with stand alone access points, as I 
> have here.  It's plain Ethernet traffic, after the WiFi has been 
> handled.  Other than apparent bandwidth, there's no way a user could 
> tell if they were connected over WiFi or Ethernet, as the WiFi 
> function is completely transparent in that regard.  As an experiment, 
> ping a device connected via WiFi and then check your arp cache.  You 
> will see the MAC address of that device, which means it's effectively 
> on the switch or "bridged"¹ to the network.  If it passed through the 
> router, you would not see any MAC for it, though the router's MAC 
> would be listed.
>
> 1. A bridge and a switch are logically the same device in that they 
> work at the Ethernet level and reduce/eliminate collision domains.
>

Forgot to mention, there are a couple of good WiFi books from O'Reilly, 
written by Matthew Gast.  They are "802.11 Networks" and "802.11n A 
Survival Guide"  The 802.11 Networks book goes into great deal on how 
WiFi devices are made to appear as though they're connected via Ethernet.

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