Book Image

Linux Networking Cookbook

By : Agnello Dsouza, Gregory Boyce
5 (1)
Book Image

Linux Networking Cookbook

5 (1)
By: Agnello Dsouza, Gregory Boyce

Overview of this book

Linux can be configured as a networked workstation, a DNS server, a mail server, a firewall, a gateway router, and many other things. These are all part of administration tasks, hence network administration is one of the main tasks of Linux system administration. By knowing how to configure system network interfaces in a reliable and optimal manner, Linux administrators can deploy and configure several network services including file, web, mail, and servers while working in large enterprise environments. Starting with a simple Linux router that passes traffic between two private networks, you will see how to enable NAT on the router in order to allow Internet access from the network, and will also enable DHCP on the network to ease configuration of client systems. You will then move on to configuring your own DNS server on your local network using bind9 and tying it into your DHCP server to allow automatic configuration of local hostnames. You will then future enable your network by setting up IPv6 via tunnel providers. Moving on, we’ll configure Samba to centralize authentication for your network services; we will also configure Linux client to leverage it for authentication, and set up a RADIUS server that uses the directory server for authentication. Toward the end, you will have a network with a number of services running on it, and will implement monitoring in order to detect problems as they occur.
Table of Contents (19 chapters)
Linux Networking Cookbook
Credits
About the Author
About the Reviewer
www.PacktPub.com
Preface
Index

Installing a Snort IDS


To start monitoring our network for irregular traffic, we are going to start by installing a Snort IDS. Snort is one of the oldest and most feature packed Open Source Network Intrusion Detection Systems (NIDS). It is free for use, and there is a wide collection of rules freely available for it, as well as information and support on designing your own custom checks.

How to do it…

  1. Install the snort daemon package:

    sudo apt-get install snort
    
  2. When prompted, enter the network interface which you want to monitor. For our example, we will use eth0, which on our router is the LAN port.

  3. Next, enter the network range which you consider local. We will use 10.0.0.0/24, which we previously defined as the LAN range. If desired, you can specify multiple CIDR blocks by having them comma separated without any whitespace.

How it works…

The network range(s) that you defined as local in the third step are used to populate the $HOME_NET setting within Snort. $HOME_NET and $EXTERNAL_NET are...