Ubuntu Gateway Server - Introduction

During the next several weeks, I am going to be configuring Ubuntu Linux Server as an Internet Gateway and Router. The server will perform several key tasks:

1. NAT Internet traffic from my internal network to the Internet
2. Function as a DNS server for my internal network
3. Function as a DHCP server for my internal network
4. Establish and maintain a slightly complex IPSEC VPN scenario

Throughout these articles, I will be setting up a fake test scenario inside VMWare. I will be setting up three VMWare machines. Two of them will be Ubuntu Linux Server and one of them will be Windows Server 2003 w/ SP2 running ISA Server 2006 w/ SP1.

During this simulation, each VMWare computer will be assigned two network adapters: one for the computer's "internal" network and one for its "external" network. In all reality, the external network will be my true private network. The following IP settings will comprise my simulation network:

Ubuntu Server 1:

• Public IP address: 192.168.27.20
• Public Netmask: 255.255.255.0
• Internal IP address: 192.168.50.1
• Internal Netmask: 255.255.255.0

Ubuntu Server 2:

• Public IP address: 192.168.27.21
• Public Netmask: 255.255.255.0
• Internal IP address: 192.168.51.1
• Internal Netmask: 255.255.255.0

Windows 2003 Server:

• Public IP address: 192.168.27.22
• Public Netmask: 255.255.255.0
• Internal IP address: 192.168.51.1
• Internal Netmask: 255.255.255.0