Macbook vs. WRT54G wireless router
Today I brought my Macbook to my mom’s house for the first time. Like me, she has a Linksys wireless router, but unlike me she is connected to the internet via Verizon DSL. Now, her Windows PC and laptop connect to the network through the router automatically (there’s no wi-fi password since this is northern Vermont and the next house is a mile away).
The Macbook likewise connected instantly to the wi-fi network, but couldn’t see the internet. When I’d try to ping a Web address, I just got “no route to host.” Very sad.
Fine, let’s take a look at the router and see what’s up. I opened the default Linksys IP address, 192.168.1.1 and entered the default login, which is a blank user ID and the password “admin.” No dice. Did I change the password when I set this up? WTF. After much frustration I turned on the PC and checked the network configuration via the ipconfig command. Hmm, the router appears to be at 192.168.2.1. Indeed, when I went to that IP, I was able to log in with the default password. Why had this been changed? I have no idea. Perhaps it has something to with Verizon — I wasn’t here when my mom switched ISPs.
Anyway, after that I was able to see the DHCP clients table, and indeed there were IP addresses assigned to both the Airport and ethernet for my Macbook. However, when I checked the Network control panel on the mac, there was apparently no IP address defined in the TCP/IP settings. WTF. I switched to manual configuration and entered the IP address, subnet mask and the IP of the router.
When I re-opened the Network control panel, it claimed I was now connected to the Interweb. Yay! But still, when I tried to ping a Web address, it still claimed it could not find the host.
Well, the “DNS Servers” box was still blank — that might account for not knowing any hosts (duh). But how do I discover my DNS server (I am a front-end dev, I don’t know this server-side crap 
) After a little Googling, I discovered that I just need to do “ipconfig /all” in order to see my DNS servers.
Oddly (to me) the DNS server was 192.168.1.1 — the usual IP address of the router. I entered that in the DNS servers field, hit Apply, and boom! Internets!
Conclusion
The procedure was exactly the same for both the Airport and the Ethernet adapters: First, get the Macbook adapter’s IP address from the Linksys’ DHCP clients table. Then, on the PC, do ipconfig /all. Then on the Mac’s Network control panel, choose manual TCP/IP configuration and just copy the IPs for Subnet Mask, Router and DNS Server from the PC.