Jizzomaru i crawl this world bit by bit and never stop until reach the top

Setting Internet Sharing (ICS) on Ubuntu 9.04

This is the second time i turning back my lovely desktop pc “The Killer-Bee” to use Linux base OS, i really interested with the latest release from Ubuntu “Jaunty Jackalope” it’s really amazed me how she recognize all my hardware PC, especially my EVDO cdma Modem (SMART) coz there was no official linux driver release from the provider.

The installation it’s more user friendly, i really like the new look of partition manager on the installation step it’s easy to manage, but now I dont want to tell how to install ubuntu on pc or laptop,  I rather want to share and discuss how to share your internet connection in ubuntu, i know that the official document of ubuntu already discuss how to do it but this is my own experience, it took me 2 days to figure it out i know it sound so stupid but what the heck i’m really noob with linux, thats why i want to share my experience here.

ok lets get started:

# In my case i want to connect my |modem|–>|desktop pc|–> |switch hub| –>|Laptop|
# so the connection will be using straight cable
# first step – connecting to the internet using modem, that mean the connection will be ppp0
# check ur modem connection (open you terminal session: Applications–>Accessories–>Terminal)

ifconfig ppp0

# Second step – set my ethernet with static ip, in this case my ethernet card is eth0

ifconfig eth0 192.168.0.1 netmask 255.255.255.0

# or you can do it using Network Connections (System–>Preferences–>Network Connections)

# after you set your eth0 with static ip, now download this package dnsmasq and iptables

sudo apt-get install dnsmasq iptables

# after the package is installed, edit the /etc/dnsmasq.conf

sudo gedit /etc/dnsmasq.conf

# add this line and save it

listen-address=192.168.0.1
interface=eth1
dhcp-range=192.168.0.100,192.168.0.250,72h

# edit /etc/rc.local

sudo gedit /etc/rc.local

# add this line and save it

wanint=ppp0
localnet=192.168.0.0/24

echo 1 > /proc/sys/net/ipv4/ip_forward
iptables -t nat -A POSTROUTING -s $localnet -d 0.0.0.0/0 -o $wanint -j MASQUERADE

Congrats… now you can share your internet connection without the need to setting up at the client side, because the package of dnsmasq will make your desktop act as DNS and DHCP server, then the iptables do the nat thing….

regards,