Well now we have a better picture.
[adsl modem (mt882)](lan)<-- wire -->(lan)[switch](lan)<-- wire -->(lan)[wireless ap (wa601g)]
However, it still raises a few more questions.
Your typical ISP limits home and small office users to one public IP. In order for more than one client on your network to have Internet access, you need a router. The router assigns itself the public IP on its WAN port, then creates a local IP network behind it (e.g., 192.168.1.x) and distributes local IP addresses using its own DHPC server (e.g., 192.168.1.100, 192.168.1.101, …).
But I don’t see a router in this picture. Granted, you don’t need a router if your ISP supports *multiple* public IPs, one for each client on your network. But if they don’t, then I’m puzzled. How are you sharing Internet access within this configuration?
I’ve also noticed the wireless AP (WA601G) supports its own DHCP server. Is this enabled or disabled?
If your ISP supports multiple public IPs, then it would make sense your own DHCP server was disabled. OTOH, if your own DHPC server is enabled, then there’s no guarantee which DHPC server, the one from the ISP or your own, responds first to DHCP requests from your clients, whether they’re connected to the wireless AP or the switch. IOW, it’s just pure luck whether they get a public IP from the ISP, or a local IP from your wireless AP!
This is why it’s so difficult to provide an answer based on the scant information in your original post, or even your most recent followup. In the networking world, it’s these small details that can make a huge difference. Something just doesn’t add up here. At least it’s not typical.
As I said before, it’s entirely possible this configuration works, but it requires a specific set of configuration settings for that to be the case. If your ISP is providing multiple public IPs and the wireless AP had its DHCP server disabled, that would be one valid example. In that case, *every* client, wired and wireless, would be on the public IP network. The trouble I’m having is I find that highly unlikely. So either I still don’t have the correct picture, or more likely, this configuration is just not right. And until it is right, making further modifications to the laptop is ill-advised (it might not even be necessary if the network can be configured properly).