Use Ubuntu7.04 as a server

There are several computers, hoping to use one of them as the server and provide routing and sharing services for other computers. to ensure stability and security, choose linux as the server system, ubuntu is a very easy-to-use Linux release, which I will use. First of all, the hardware must have a computer that can install Ubuntu7.04 (generally not all new computers can be installed), and there are two NICs as gateways for two network segments. The installation configuration is directly installed with Ubuntu7.04. The installation is successful and will soon be complete. However

There are several computers, hoping to use one of them as the server and provide routing and sharing services for other computers. to ensure stability and security, choose linux as the server system, ubuntu is a very easy-to-use Linux release, which I will use.

Hardware

First of all, you must have a computer that can be installed with Ubuntu7.04 (not all new computers can be installed), and two NICs are available as gateways for two network segments.

Install configurations

Install Ubuntu7.04 directly. The installation was successful and soon completed. Then configure the network and set the network adapter eth0 to 192.168.1.234, because the original network segment is 192.168.1.0/24, and the other network adapter eth1 is configured as the gateway 192.168.2.1 with the network segment 192.168.2.0/24, in this way, all other computers are clients in the LAN 192.168.2.0/24.

Use the route-n command to view the route table information:

Kernel IP route table

Target gateway subnet mask flag hop reference Interface

192.168.2.0 0.0.0.0 255.255.255.0 U 0 0 0 eth2

192.168.1.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0

169.254.0.0 0.0.0.0 255.255.0.0 U 1000 0 0 eth0

0.0.0.0 192.168.1.1 0.0.0.0 UG 0 0 0 eth0

One is the gateway of 192.168.1.0/24, the other is the gateway of 192.168.2.0/24, the other is the loop, and the last is the default route.

Next, IP Forwarding. In many documents, use the following command to enable I forwarding:

Sudo echo "1">/proc/sys/net/ipv4/ip_forward

But I don't know why I always say I have no operation permission in Ubuntu, so I have to look for another path:

Modify/etc/sysctl. conf and add:

Net. ipv4.ip _ forward = 1

Also added:

Net. ipv4.tcp _ syncookies = 1

Net. ipv4.icmp _ echo_ignore_broadcasts = 1

This configuration sets system parameters when the system starts, so that IP Forwarding is complete.

The firewall management tool FireStarter is installed, but the following error occurs when it is started:

The device eth0 is not ready

An error occurred while starting. Run the following command:

Udo sed-I ~ "S/\/sbin \/ifconfig/env LANG = en_US \/sbin \/ifconfig/g"/etc/firestarter. sh