Sharing Internet connection with networked Windows box

For OS X
Open System Prefs - Sharing - Internet . Click on the on for the ethernet port and start.

On the windows machine say that the ip of your mac is you router.

OS 9 - Dunno never used it.

Dobby.

It's not quite as simple of that unfortunately.

Many cable connections connect via Ethernet - does yours? If so you'll need a spare Ethernet port on the Mac and a crossover cable which you'll use to connect the machines. I'm also assuming you're running OS X so excuse me if this isn't the case.

Set yourself a static IP on the Macintosh under System Prefs > Network and choose the relevant Ethernet connection. It's probably best to use 192.168.1.1 (with a subnet of 255.255.255.0). Do the same on the PC (Control Panel > Network Connections) but use the IP address 192.168.1.2. Then set the gateway address to that of the Mac. Enter the DNS server addresses on both machines. (you should have these with your cablemodem account details, or on your ISP's website)

Then you can enable Internet Sharing on the Mac (like dobbyduck said) and you should then be able to access the Internet from the PC. I've not personally done it before but in theory this is what you would need to do. Let me know if it works.

First, I have both machines connected via 100baseT through a hub. The cable modem is also connected this way. Second, I can't set a static IP. The ISP uses DHCP so the IP is assigned by the server.

Any more ideas?

Olliefelde,

If Mac, PC and Cable Modem are all connected to hub, then the Cable Modem is the gateway (if it is a Cable Modem Router).

First, determine the local IP address of your Cable Modem.  For example, 192.168.0.1.  
Internet IP Address for the Cable Modem will be assigned by ISP.

On your Mac :
IP address : 192.168.0.2
Netmask : 255.255.255.0
Gateway : 192.168.0.1 <local ip address of the cable modem>

On your PC :
IP address : 192.168.0.3
Netmask : 255.255.255.0
Gateway : 192.168.0.1 <local ip address of the cable modem>

So, you don't share internet connection thru Mac, but thru Cable Modem (if it equipped with Router function).

Does your Cable Modem support Routing?  (let me know the brand and the model, I can check it out for you).

Good luck.

Yes - perhaps look at the manual of your modem first as this will have most of the information you need.

The fact the modem is assigned a dynamic IP shouldn't be a problem but it will need to be capable of NAT i.e. the router must be able to create its own 'private' network behind the connection to the Internet.

Any of this would be done from the configration program or web interface for the router itself. How do you normally configure the router?

I don't configure the "router". The ISP uses DHCP. According to my mac's network setup, my mac is the holder of the IP address.

Okay I see what's going on now.

The fact the Mac is allocated the IP means you have to share it from the Mac itself (although I'm still confused that the modem is plugged in via Ethernet).

You will need to install an additional Ethernet port in your machine. These are fairly easy to obtain - most common chipsets are supported by Mac OS X as far as I know but of course check the spec of the card in question.

Once you've installed the second card, you can follow the instructions in my first response and it should work.

Olliefelde,

Perhaps it might help us, can you tell us what's the brand and the type of your Cable Modem?

I think I got the picture now.

It was : (internet) <---cable---> (cable modem) <---ethernet---> (G4/400 Mac).

You want to share it with Windows, so you changed the configuration to :

(internet) <--cable--> (cable modem) <--ethernet--> (switch/hub) <--ethernet--> (G4/400 Mac)
                                                                                  ^
                                                                                   |------ethernet---> (Windows)

Right?

You can do as suggested by in-effect.  It will become (starting with cable modem)

(cable modem) <--ethernet--> (g4/400) <--ethernet--> (switch/hub, or windows PC).

In this configuration, windows will share the internet connection on G4. (in other words, G4 as the gateway).

Good luck.

You need to do a few things:

1 IP aliasing see here for instructions:
http://developer.apple.com/documentation/Darwin/Conceptual/howto/network_config/network_config.html

2 add a route to let your mac route packets
you can use route add for temporary (look at the man page for details)
I can't remeber the file for mac os to edit, but it's /etc/rc.d/rc.local in linux.  Maybe you can find it somewhere.  Just add the route to the end of the file.

3 set the Ip address on the pc & mac (during step one) with the IP addy of the mac as the gateway for the pc.  make sure to use the same mask.

good luck!