Linux Share a Dial Up Internet Connection

To share a dial-up Internet connection on a Linux machine, you will need to perform the following steps:

1. Install the ppp and iptables packages, if they are not already installed. You can do this using your distribution's package manager, such as apt or yum.

2. Configure the dial-up connection using the wvdial or pppconfig utility. This will create a connection configuration file in the /etc/ppp directory.

3. Enable IP forwarding by adding the following line to the /etc/sysctl.conf file:

net.ipv4.ip_forward = 1

4. Reload the kernel parameters by running the following command:

sysctl -p

5. Set up the NAT (Network Address Translation) using the iptables utility. For example, to enable NAT for the eth0 interface and the ppp0 connection, run the following commands:

iptables -t nat -A POSTROUTING -o ppp0 -j MASQUERADE
iptables -A FORWARD -i eth0 -o ppp0 -j ACCEPT

6. Save the iptables rules so that they will be applied on boot. You can do this using the iptables-save command.

7. You should now be able to share the dial-up Internet connection on your Linux machine with other devices on the same network.