Mac OS X: Networking Problem (iBook -> linksys router)

Networking Problem (iBook -> linksys router)

Hi all, hopefully there's some networking guru out there who can help me with this one. Here's the situation:

I have a cable modem (Motorola) and an iBook (G3-600 dual-USB). I purchased a Linksys Wireless-B router to go between them and add wireless capabilities (the iBook has an Airport card). Now, when I hook up the iBook to the router via cable it finds DHCP but is not able to ping or http what claims to be the router at 192.168.1.1. So it finds the router enough to make the light blink on the front, and assign an IP address (in a weird way, more on that later) but not enough to do anything with the connection beyond DHCP. Wireless is same deal, Linksys' documentation says you have to configure it with a wired connection before you can turn on the 802.11b, which is understandable for security purposes.

My original thought was a DHCP conflict between the cablemodem and the router. But when the cablemodem is totally disconnected the same problem occurs. now here's the two funny things that suggest to me this is something in the iBook's config (I am on 10.3.2 here): #1 -- I cannot renew my DHCP lease until I reboot, like some Windows peon. In other words it keeps self-assigning IP addresses if I just plug things in without rebooting, unable to locate the DHCP. But if I reboot, it's fine when it comes up. #2 -- in ifconfig, my en0 interface frequently has 2 IP addresses assigned to it, like this:

---- what ifconfig reports (excerpt):

en0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
inet 192.168.1.100 netmask 0xffffff00 broadcast 192.168.1.255 <-- the IP assigned to me by DHCP or manual
inet 192.168.1.1 netmask 0xffffff00 broadcast 192.168.1.255 <-- the mysterious IP assignment
ether 00:03: blahblah
media: autoselect (100baseTX <full-duplex>) status: active
supported media: none autoselect 10baseT/UTP <half-duplex> 10baseT/UTP <full-duplex> 10baseT/UTP <full-duplex,hw-loopback> 100baseTX <half-duplex> 100baseTX <full-duplex> 100baseTX <full-duplex,hw-loopback>

blah blah, en1, fw0 config info (all inactive)

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If apache is on then 192.168.1.1 comes up as my localhost web server default page. If not it just doesn't connect to anything.

I have shut off all sharing and all port configs except Ethernet in network prefs. If I go sudo ifconfig en0 192.168.1.100 or whatever it will eliminate the duplicate IP address in ifconfig, but the GUi tools don't catch it because they only assume one IP per network interface. Coincidentally this 192.168.1.1 IP is the admin IP for the Linksys router, but it appears in my ifconfig whether or not the router is hooked up. It's something else. If I do eliminate it manually via ifconfig, I can no longer ping myself at 192.168.1.1, but I also can't ping/http the ROUTER either even if it's hooked up.

And here's the final clue. In Sharing Preferences, when I click on the 'Firewall' tab, it says 'Other firewall software is running on your computer. Please turn it off before you can adjust the firewall settings here'. And I'm like what the hell because I am not aware of any firewall software I am running (Virex etc is not installed on this machine).

Any ideas? This is a tough one.