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
About the Author
About the Reviewer

Detecting systems on your network with NMAP

If you have heard of nmap before, it was likely as a hacker tool. These days it is most commonly used as a port scanner, but it actually started its life as a network-mapping tool for discovering hosts. In fact, nmap stands for Network Mapper. It can utilize ICMP, UDP, and TCP.

Let us look at how to utilize it to discover what systems exist on your network.

How to do it…

First, we need to make sure that we have nmap installed. Luckily, it is a common enough tool to be available in the package repository for your selected distribution, and it will be accessible either by running sudo apt-get install nmap or sudo yum install nmap.

Next, we will do a simple ICMP sweep of the network to see who responds:

# nmap -sP
Starting Nmap 6.40 ( ) at 2016-05-03 15:43 EDT
Nmap scan report for
Host is up (0.00053s latency).
MAC Address: 52:54:00:65:7D:0A (QEMU Virtual NIC)
Nmap scan report for
Host is up.
Nmap done:...