[Bismark-devel] switching issue on device

[Kim Hawtin]

On 18/04/11 00:22, Nick Feamster wrote:
> On Apr 17, 2011, at 10:46 AM, Dave Taht wrote:
>> I'm mildly confused as to your topology here. Diagram?
>>
>> You are behind NAT by default, so if you try to ping through the WAN
> port to something anything inside the LAN, those machines will be unreachable.
> You should however, be able to ping from the wireless to anywhere wired,
> LAN or WAN port. If you have AP isolation turned on in the wireless side,
> you cannot ping any other wireless connection, and I'm unsure what the
> behavior is for wired to wireless in that case.
>
> I'm just talking about my LAN here:
>
>  SERVER<----(2.4 GHz wireless, SSID "foo") ---->  WNDR3700<---- (wired LAN port) ---->  Access Point 2
>
> * When I associate to AP2, I can ping SERVER, and resolve MDNS names.
> * When I log into WNDR, I can ping SERVER
> * When I associate to the WNDR3700, I can neither ping the server, nor resolve MDNS names.
>
> So, isn't it strange that everything works when I'm connected via AP2,
> but not via the WNDR?  By my reasoning, all of the traffic that I'm
> sending when I'm connected via AP2 would have to go through the WNDR anyhow...

I am not sure how relevant my experience is here, as I am not using a 
WNDR3700. I have seen this behavior on other APs. I have a hunch that 
its related to how ARP is treated on the AP. In my case specifically on 
WPA2 on a modern Billion device that does ADSL2+/AP/VoIP. This behavior 
generally does not seem to be an issue on an open network or using WEP. 
I noticed this last weekend when I was setting up my server at home to 
to builds on, transfering files around with rsync/scp/etc

Only when *both* hosts on the wireless have ping'd the AP can then you 
ping the other hosts from wireless to wireless...

([laptop A], [laptop B]) --wifi-wpa2--> [AP] <--wired-- [server]

For example I can not ping [laptop B] from [laptop A], both being on the 
wireless using WPA2, until I ping the AP from both laptops. I can 
however ping the [server] from both laptops. However I can not ping 
either latptop from [server] until the laptop has ping'd [AP]. There is 
currently no mdns in use by any of these devices.

Perhaps the AP is building an internal table using mdns to 
allow/identify traffic across its interfaces?

regards,

Kim