12.04 network issues

[PermNoob]

I have two very similar laptops running 12.04 ubuntu. the "bad" one a dell inspiron 6400, core duo, and the "good" one a dell latitude E6400 XFR. the inspiron i updgraded ubuntu from the latest LTS ubuntu to 12.04 recently, the latitude is a fresh dual boot install, with windows 7 being the other OS, and I installed 12.04 as beta very early last month. I am running 32 bit on both machines, despite the latitude being a 64 bit

I have a clear WIX FBR 117 modem/wifi router. both laptops worked peachy keen on WIFI. suddenly the latitude gets kicked off fairly often, but still works, and the Inspiron conects and gets kicked on a regular basis, but at no time can i connect to the net on the inspiron. the latitude i have full net acess as long as I am connected. The second issue is with either machine I can no longer see the modem. when connected by WIFI if I try to navigate to 192.168.15.1 or 10.42.0.1, I get a time out error.

both of these issues appeared at the same time ~2 weeks ago. My roomates macbook seems to work fine on the wireless network. everything on the network has been power cycled a hundred times since these issues began. the fact both machines developed a problem at the same time makes me suspicious.

what is this hell? what info can I post to help out w/ diagnosis

[PermNoob]

OK the ethernet LAN issue on the "bad" laptop was a config issue, a cat must have modified it somehow... they are tallented, no idea why I would have disable DHCP. I am digging into my modem right now to see if that is the issue.

[n0wje]

Permanoob try disabling IPV6 in network settings and reboot or restart network. I am running a Dell M5030 Laptop 64bit 12.04 install and on WIFI too. I am new to giving advice but will help as much as I can.