GeekLab

In this article I'm covering the use of old-style dhcp and tftp, which is useful for company networks that have/need a complete dhcp server running. Personally, for smaller setups, I now prefer dnsmasq to do the job.

Booting from PXE

With most modern onboard and PCI network interface cards (NICs), it's possible to boot from the network. This system is called PXE.

Why would I want to boot from the network?

For installation of a computer without using CDs/DVD's

For thin clients

For booting diagnostic software

What is needed for PXE Boot?

a network card that supports PXE

a bios that supports plugin boot cards

a DHCP server

a TFTP server

some (open source) software you want to run

How to set up PXE boot?

As I'm running (a variant of) RedHat Linux, I only cover how to set up PXE boot using Linux components. But there are Windows solutions as well. (Google it!)

Step 1: set up DHCP

When the NIC boots, it needs to get IP settings. Setup dhcp as usual. Now add these lines to the configuration:

next-server <em>192.168.1.254</em>;

filename "/pxelinux.0";

In the place of 192.168.1.254, you need to enter your own tftp server address. On my RH system, I installed the dhcp server using yum install dhcp, then configured /etc/dhcpd.conf as follows:

ddns-update-style ad-hoc;

authoritative;

log-facility local0;

default-lease-time 86400;

max-lease-time 86400;

subnet 192.168.1.0 netmask 255.255.255.0{

    range 192.168.1.100 192.168.1.200; <em>#limited range</em>

   option subnet-mask 255.255.255.0;

    option broadcast-address 192.168.1.255;

    option routers 192.168.1.254;

    option domain-name-servers 192.168.1.254;

    option domain-name "lan";

    next-server 192.168.1.254;

    filename "/pxelinux.0";

}

Step 2: set up TFTP

Download and install a tftp server. Most Linuxes ship their own, which you can install using yum (RedHat), yast (SuSE), apt-get (debian/ubuntu) or similar. On my RedHat, I install a tftp server by running yum install tftp-server. Then I enable it using /sbin/chkconfig tftp on and reload xinetd: /sbin/service xinetd restart.

Step 3: download and install syslinux

On my RedHat system, I install syslinux by running yum install syslinux. I then copy the syslinux.0 file to /tftpboot: cp /usr/lib/syslinux/pxelinux.0 /tftpboot

Optional: Firewall

On a default RedHat installation, the firewall is enabled. You may need to open port 67-69 for dhcpd and tftp to function and port 53 for DNS.

Links

More details are described on http://syslinux.zytor.com/wiki/index.php/PXELINUX© GeekLabInfo