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

Configuring IPv4 permanently


In the previous section we configured the network interface, but this configuration is only valid while the system is up and running. A reboot will clear this configuration, unless you take steps to make sure that it is configured on each boot. This configuration will be specific to the distribution that you are running, although most distributions fall under either the Debian or Red Hat methods.

How to do it…

Let' see how it works in Debian/Ubuntu:

  1. Add eth0 configuration to /etc/network/interfaces:

    auto eth0
    iface eth0 inet static
        address 10.0.0.1
        netmask 255.255.255.0
  2. Bring up the network interface:

    # ifup eth0

Let' see how it works in Red Hat/CentOS:

  1. Add the eth0 configuration to /etc/sysconfig/network-scripts/ifcfg-eth0:

    DEVICE=eth0
    BOOTPROTO=none
    ONBOOT=yes
    NETWORK=10.0.0.0
    NETMASK=255.255.255.0
    IPADDR=10.0.0.1
    USERCTL=no
  2. Bring up the network interface:

    # ifup eth0

How it works…

Linux distributions are configured through init systems, such as Upstart, SystemD, or SysVInit. During the initialization process, the interfaces, or ifcfg-eth0 files, are used as a configuration for the networking setup scripts. These scripts then use the same ip commands, or possibly ifconfig commands to set up and bring up the network interface.