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I have an extremely strange problem with an Airlink101 AP431W access point. I have a small sub-network of three devices linked to a switch. The network was moved to a different room and now has to connected wirelessly instead of wired. The wireless and wired networks are bridged at their common source. This should be a no brainer. And with a WRT54GS configured as an access point and with all ports bridged, everything works fine.

But with the AP431W (AP431W and all three devices connected to a cheapo gigabit switch), only the first MAC address seen works. If I disconnect all three machines from the switch and reboot the access point, whichever device I connect to the switch first works, and the other two devices cannot reach any host over the access point. (The three devices can reach each other when they're all connected to the switch, but always two of the devices can't reach any devices over the WiFi link.)

The AP431W has a static IP address and management works fine in all configurations. I use no authentication, but 64-bit WEP. It's configured as an AP client. Access control is disabled. Advanced wireless settings are all at their defaults.

It looks like the AP431W will only bridge the first MAC it sees. Has anyone heard of anything like this?!

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up vote 2 down vote accepted

It's configured as an AP client.

Sounds like the AP client is working as expected, except that you have clouded the picture by introducing a switch and two other hosts. The "AP client" is supposed to support only one (wired) host. You cannot use a switch to expand the backend of the AP431W configured as an AP client. Perhaps a (wired) router instead of the switch would work, but that adds a level of network complexity that you way not want.

Sounds like you really should be using the AP431W in bridge mode, but then you will need another AP431W access point to build a proper wireless bridge.

Or you need to provide an access point client for each of your "devices". Or if any of these "devices" has a USB port that supports a USB-to-802.11 adapter, then that is another way to provide each "device" with wireless connectivity.


Consider using a wireless router in wireless bridge mode. You may have to use alternate firmware like DD-WRT.
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How can the device even tell if there's more than one host behind it? (As opposed to, say, a single host with multiple MAC addresses.) And "bridge" wasn't a configuration option as far as I could tell. I need to keep these three devices wired to each other. – David Schwartz Oct 3 '11 at 7:13
There is simply no way the device could tell whether there's one host or multiple hosts behind a switch. It's impossible. AP client is a WiFi mode that should make it a client of my access point, which is what I want. (And it in fact does this.) The symptom is that it seems to lock onto the first MAC address, as if it were sensible to assume a host only has one MAC address (which is obvious nonsense). – David Schwartz Oct 3 '11 at 7:27
WDS mode makes it rebroadcast wireless traffic. I don't want that. I just want it to be a client of my existing access point. And if it assumes that a host has only a single MAC address, it's hopelessly broken since that's nonsense. (And maybe that's the answer, this device is hopelessly broken.) – David Schwartz Oct 3 '11 at 7:28
"Bridge" mode is also called "WDS". Your experience shows that the AP client only supports one (the first one that connects) host. A NIC can only have a single MAC address. – sawdust Oct 3 '11 at 7:28
Even if that's true, a host can have any number of NICs and bridge them internally. VM software does this. Also, a host can have a VPN that extends the LAN. The idea that a host can only accept traffic to a single unicast MAC is hopelessly broken. – David Schwartz Oct 3 '11 at 7:30

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