How to Internet connection Sharing( ICS )

**zaphod777** · January 10th, 2010

Originally Posted by ssl432

If this question has already been answered I couldn't find it but a link would be welcomed.

Here goes:

I have an ancient laptop with a broken screen that I would like to use as a wireless Internet receiver. I want it to receive Internet over a usb wireless nic (wlan0) and share it along with dhcp and dynamic ip addressing service through it's built in nic (eth0) to the rest of my network via a 4 port Ethernet switch with an up-link port (it is just a dummy switch, it doesn't do dhcp or anything else like that). I have followed the instructions from the link shown above. Here is my difficulty; If I connect eth0 to a regular port on the switch firestarter starts up just fine and reports no errors, however in order to share the Internet out to the rest of my network I believe I need to plug into the up-link port and this causes firestarter to tell me "Failed to start firewall, the device eth0 is not ready...." as if it was completely disconnected. I have been using a newish (windows vista) laptop that belongs to my work to get to the internet up to this point and everything works ok with it hooked to the up-link port on the switch using m-sft's ics. I had hoped that I could just slip this ubuntu machine in in it's stead but I am stymied.

This might be just a basic networking problem and not an Ubuntu issue at all, but as I said, it works somehow with my current setup but the ubuntu laptop just won't do it. I am not a particularly command line savvy person which is why I'm trying to use firestarter, so if this can be explained without a long series of command line references I'll love Ubuntu forever, if not I'll just like Ubuntu as a friend and try to muddle through somehow. Any help at all will be welcome.

uplink port is only needed for connecting switch to switch. You laptop can connect to the normal switch port. Most uplink ports also have a button next to it if you push the button then it will change from uplink to normal switch port.

**sldavid** · August 10th, 2010

thanks Zaphod777.

I followed the first of the two links (https://help.ubuntu.com/community/In...nectionSharing) and from there used the option - GUI Method via Network Manager (Ubuntu 9.10 and up). And....
I was sharing my wireless laptop Internet connection with the rest of my home network. Still can't believe is was that easy.

**ibrahim.k** · August 11th, 2010

thnx for sharing knowledge with us.
may I ask what settings did you use on the desktop ?
as to me i want to share my laptop wireless internet with my desktop via ethernet.
from ipv4 i choose the shared to other computers option.

Originally Posted by sldavid

thanks Zaphod777.

I followed the first of the two links (https://help.ubuntu.com/community/In...nectionSharing) and from there used the option - GUI Method via Network Manager (Ubuntu 9.10 and up). And....
I was sharing my wireless laptop Internet connection with the rest of my home network. Still can't believe is was that easy.

**zaphod777** · August 11th, 2010

Originally Posted by sldavid

thanks Zaphod777.

I followed the first of the two links (https://help.ubuntu.com/community/In...nectionSharing) and from there used the option - GUI Method via Network Manager (Ubuntu 9.10 and up). And....
I was sharing my wireless laptop Internet connection with the rest of my home network. Still can't believe is was that easy.

Glad to help there is a lot of good documentation in the official documentation pages. I think a lot of people don't even know it is there.

**gvoima** · August 14th, 2010

Just a reminder..

I'm sharing a ppp connection on Karmic to my local network through the onboard nic. The network sharing described in the ubuntu documentation works fine, except that I start my ppp connection after bootup. It uses the package dnsmasq-base and it doesn't poll the connections correclty.
So restarting dnsmasq after initializing the ppp connection, it works fine.

If anyone is having this problem on Karmic, this might be the possibility.

**Schuby007** · February 2nd, 2011

Hi,

I'm trying to share my wireless internet connection via my laptop running 10.10 with my desktop running 10.04.

I followed https://help.ubuntu.com/community/In...nectionSharing "GUI Method via Network Manager" and set my eth0 connection on my laptop to "Shared To Other Computers". I then plug an ethernet cable into my eth0 port on my laptop and into the eth0 port on my desktop and my laptop pops-up and says Auto eth0 Connection Established but nothing happens on my desktop, and when I try to connect to Auto eth0 on my desktop I see the wireless meter flash for about 30 seconds and then it says Wired connection disconnected".

Anyone know what's going on? Do I need to use a crossover cable?