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How to connect an access point with a switch

Last response: in Wireless Networking
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March 2, 2011 11:43:20 AM

Hello,
Am trying to connect 3 pcs connected to a Dlink 8 port switch through a Dlink WL2100 Access point connected as an AP Client to the main network. Only 1 pc is able to see the main network and am having none of the other 2pcs are able to see the main network. The 3 pcs are able to see each other.
March 2, 2011 1:42:09 PM

Since I'm not familiar w/ this particular WAP, I can't be 100% sure. But what I suspect is this WAP cannot handle multiple clients when configured for AP Client mode, esp. given this an older WAP (manual says it dates back to May 2006). Let me explain why this might be the case.

When manufacturers first started creating these WAPs that could handle different types of configurations (AP Client, Repeater, etc.), what they often failed to do was add the programming to support multiple MAC addresses beyond the WAP. The wireless protocol only supports one MAC address from station to station. Any attempt to use a additional MAC addresses just won’t work, you get no response. In order to make it work, the manufacturer needs to add programming to (for lack of a better term) “NAT” the MAC addresses. IOW, the WAP maps the various MAC addresses behind it to a single MAC address. It’s very similar to your router’s NAT, which maps the single public IP provided by the ISP to multiple local IP addresses behind it. The use of NAT gives the “illusion” that everyone has their own private IP/session, when it fact this is not the case.

If you try connecting different devices first, and they work, and subsequent devices always fail, that’s pretty much a confirmation of the problem. It also explains why they can still see each other; they don’t need to cross the AP client bridge for those purposes.

It’s a shame, but many manufacturers simply didn’t add this programming (sometimes out of ignorance, sometimes laziness, sometimes they just didn’t care). Nowadays, almost all manufacturers provide this programming. But just a few short years ago, this was a fairly common problem. So if you have one of these older devices, you’re out of luck. All you can hope for is perhaps a firmware update that might have added this programming. But there’s no other way to fix it.

P.S. Well, I suppose one way to fix it would be to place a router behind the AP client. IOW, if you connect any ol’ crappy router’s WAN port behind the AP client, you are, in effect, limiting that connection to a single MAC address! Now the MAC addresses of those other devices never cross the WAN port and all is well. Of course, that might introduce other problems. Now each of those clients in on a different subnet and protected by a firewall (although you may be able to disable it in some cases). What ppl usually want for their internal network is transparency, where all devices share the same subnet as the primary router. So this may or may not be a solution for you.

!