Can't share internet connection via firewire - missing something obvious?

Question

I have my G4 933 connected via ethernet to a Dynalink RTA100+ DSL modem/router. Would like to share this internet connection with anther G4 450 (time warp here) over firewire until I sort a proper router... both are running on 10.4.11
I connected the computers with firewire cable and configured the firewire ports Manually (as I couldn't get DHCP to populate them in the right range).
Tried initially turning on Personal File and Web Sharing on each, but couldn't get a Ping to go through g4 to g4, even though I can see each firewire port's ip in each other's routing table info...
Also turned on Internet Sharing over Firewire port from Ethernet but G4 450 can't connect.
Read somewhere that you can't do both, so have reverted to just trying to get the Internet Sharing working (as that's all the kids really want on their computer!)
Dug around in the modem for ages tried it in Bridge mode, couldn't connect either computer to internet then so have gone back to normal PPP settings with DHCP.
*Port settings*
_The G4 933:_
Built-in Ethernet:
Type: Ethernet
Hardware: Ethernet
BSD Device Name: en0
IPv4 Addresses: 192.168.1.3
IPv4:
Addresses: 192.168.1.3
Configuration Method: DHCP
Interface Name: en0
Router: 192.168.1.1
Subnet Masks: 255.255.255.0
DNS:
Server Addresses: 192.168.1.1
DHCP Server Responses:
Domain Name Servers: 192.168.1.1
Lease Duration (seconds): 0
DHCP Message Type: 0x05
Routers: 192.168.1.1
Server Identifier: 192.168.1.1
Subnet Mask: 255.255.255.0
Proxies:
Proxy Configuration Method: Manual
ExcludeSimpleHostnames: 0
FTP Passive Mode: Yes
Gopher Proxy Enabled: No
HTTP Proxy Enabled: No
HTTPS Proxy Enabled: No
Auto Discovery Enabled: No
RTSP Proxy Enabled: No
SOCKS Proxy Enabled: No
Ethernet:
MAC Address: blahdy blah
Media Options: Full Duplex
Media Subtype: 100baseTX
Built-in FireWire:
Type: FireWire
Hardware: FireWire
BSD Device Name: fw1
IPv4 Addresses: 192.168.3.1
IPv4:
Addresses: 192.168.3.1
Configuration Method: Manual
Interface Name: fw1
Subnet Masks: 255.255.255.0
Proxies:
Proxy Configuration Method: Manual
ExcludeSimpleHostnames: 0
FTP Passive Mode: Yes
Auto Discovery Enabled: No
Ethernet:
MAC Address: blahdy blah
Media Options: Full Duplex
Media Subtype: autoselect
_On the G4 450:_
Built-in FireWire:
Type: FireWire
Hardware: FireWire
BSD Device Name: fw0
IPv4 Addresses: 192.168.3.2
IPv4:
Addresses: 192.168.3.2
Configuration Method: Manual
Interface Name: fw0
Subnet Masks: 255.255.255.0
Proxies:
Proxy Configuration Method: Manual
ExcludeSimpleHostnames: 0
FTP Passive Mode: Yes
Auto Discovery Enabled: No
Ethernet:
MAC Address: blahdy blah
Media Options: Full Duplex
Media Subtype: autoselect
Now, nothing is actually connecting at all, yet when I do a Netstat of the Routing Table info, the firewire IPs are showing up on each G4...but still no ping, no internet.
All suggestions appreciated as I've been searching around the internet to no avail today!
Cheers
Rose

Answer 1

Hi Rose,
You can't Manually set the IPs for Internet Sharing according to Apple, (I've done it, but not consistently),
You do want the G4/450 to use DHCP, the G4/933 will likely end up handing out an IP to the 450 of 192.168.2.4, (one higher in the 3rd & 4th place, and wont work if the 933 started out as x.x.2.x), but it must do it itself to keep track of NAT within itself.
True you can't do both File & Internet Sharing at once.
On the G4/933, en0/Ethernet needs to be dragged to the top of Network>Show:>Network Port Configurations. On the G4/450, fw0/Firewire needs to be dragged to the top of Network>Show:>Network Port Configurations.
Internet Sharing needs to be OFF on the 450 & rebooted if it was ON.
As far as the Setting not sticking, there may be more, but Trash these two files on the 933 then Reboot...
/Users/YourUserName/Library/Preferences/com.apple.systempreferences.plist
/Library/Preferences/com.apple.sharing.firewall.plist