Unix box using PC ADSL

[SM_3]

I have a PC on the network with an ADSL modem.

A unix box is on the same network. Can the unix box use the ADSL modem via the network?

[Duncan Edmonstone]

Yes probably, but your PC needs to be able to:

a) route IP traffic
b) provide some type of network address translation (NAT)

and also really:
c) provide IP filtering/firewall services.

What OS is the PC running?

HTH

Duncan

[SM_3]

OS of PC is Windows 2000 Professional.

Someone mentioned that I should change the PC IP address to 192.168.0.1 and Enable Internet Connection Sharing- I tried this but then the PC and unix box could not ping each other.

The IP addresses are in /etc/hosts file repectively.

What's the significance of 192.168.0.1

[Wodisch]

Hi,

you have two choices:
- your PC does NAT (Network Address Translation), then your PC needs to do the routing to the internet, and you UN*X uses a "default route" to that PC.
- You UN*X does have PPOE (Point-to-Point Over Ethernet) protocol installed, then you point that to the ADSL-modem.

HTH,
Wodisch
PS: In germany that may be illegal... :-(

[Duncan Edmonstone]

The significance of that IP address to me is nothing! Doesn't meant that it means nothing to you though... To be honest before you even do anything on the UNIX box, you need your W2000 system set up correctly - I'm not sure whether connection sharing on W2000 just works with other W2000 boxes, or whetjer it will also work with UNIX systems - I notice you've already posted in the Windows forum - to be honest you will get much better service on this question there with respect to setting up the W2000 host.

HTH

Duncan

[Mark Fenton]

Short answer to your question is "yes"

Internet Connection Sharing on your Win2K Pro machine is quite simple. The terminology employed by Micro$oft is a little confusing, but just remember that the "shared" interface is the one that all the local computers are attached to (ie, the internal network interface), not necessarily the one attached to the internet.

I do not believe that ICS does DHCP for you, you will have to assign static IPs for other computers connected to the internet via the Win2K box. The fact that ICS forces you to use 192.168.0.0 as the internal network is merely inconvenient (though if you want to registry hack, I'm sure you could make that anything you like -- it's just not supported by M$). To the other computers on your network, the ICS looks like any other gateway, and performs IP Masquerading for you. Masquerading, not NAT. This means that there will be no easy way to get to other machines on your internal network from the internet.

I, too, echo the need to set up some sort of firewalling (Zone Alarm is a free solution that's easy to configure and fairly robust: www.zonelabs.com for the download), but there are others equally competent.

If your need is to route the UNIX box to and from the internet, then you might want to look at an external router instead of ICS. But if all you want to do is get to the internet, ICS would work just fine.

hth
Mark

[Andrew Cowan · Accepted solution]

Hi,

To setup W2K or XP with ICS you need first to get your gateway pc working through ADSL to the Internet, then setup all your client pc's without static IP addresses, and set to point to the main computer as the ICS/DHCP server. If you use the setup wizards these are all simple default choices. Microsoft has chosen that (192.168.0.1) address as the default for ICS, so when you run the wizard it will assign it to your lan inferface. Once all the pc's are setup reboot the gateway first, check the Internet connection, then boot a client. If you now open a dos window on your client and type "ipconfig /all" you should see that it has been assigned an IP address in the range 192.168.x.x, and you can ping your gateway.

The next stage is to configure Explorer by going to Tools->Options and remove all settings for your modem and replace it with connect via lan, and never dial a connection. You should now be able to get a web page from the Internet. (Repeat for each client)

The final stage is to install Zonelarm on to the ICS G/W, and remember to choose "This machine is an ICS gateway". Next install it on a client, and this time set it as an "ICS client". With both machines running the firewall in this mode, you should still be able to connect.

I have this setup at home and it works fine through BT-ADSL, it also works when I boot a client with Suse Linux.
The pitfalls are: upgrading Zonealarm seems to randomly reset the ICS settings, so you need to go to the "Main" window and reset them.
If the ICS G/W gets rebooted you have to either reboot the client(s) or run "ifconfig /release" "/renew"......

The only other obvious thing is that if the G/W is rebooted mid session, it can screw-up upgrades, downloads etc.