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

Monitoring services

A service in nagios defines a particular test which should be run. At a minimum you need to define a name for the service and the command to run in order to monitor it.

Similar to hosts, it is defined within .cfg files in /etc/nagios3/conf.d or a subdirectory. At a technical level, there is no difference between a .cfg file that defines a host versus one that defines a service. They are split in Ubuntu's default configuration just for ease of management. If you wanted to, you could have a single flat .cfg that defines all hosts, services, and users.

How to do it…

Again I like to split my services into a subdirectory, so let's look at defining a service to monitor HP Jetdirect printers by creating /etc/nagios3/conf.d/services/printer.cfg containing:

define hostgroup {
        hostgroup_name printers

define service {
        hostgroup_name                  printers
        service_description             jetdirect
        check_command                   check_hpjd