DNSMASQ

DNSMASQ

Q. Configure Dnsmasq as a Pxe Boot Server " hiren boot " ?

Q. How to configure a dnsmasq server in linux centos 6 ?

Q. step by step dnsmasq server configuration in linux centos 6 ?

IP  - 10.20.2.33

Hostname - khandwa.lokesh.com 

OS  - CentOS 6

Dnsmasq provides network infrastructure for small networks:. dnsmasq is a lightweight DNS, TFTP, PXE, router advertisement and DHCP server. It is intended to provide coupled DNS and DHCP service to a LAN. It is designed to be lightweight and have a small footprint, suitable for resource constrained routers and firewalls. It has also been widely used for tethering on Smartphone’s and portable hotspots, and to support virtual networking in virtualization frameworks.

• domain-neededThis tells dnsmasq to never pass short names to the upstream DNS servers. If the name is not in the local /etc/hosts file then “not found” will be returned.


• bogus-priv All reverse IP (10.20.x.x) lookups that are not found in /etc/hosts will be returned as “no such domain” and not forwarded to the upstream servers.


• no-resolv Do not read resolv.conf to find the servers where to lookup dns.


• no-poll Do not poll resolv.conf for changes


• server=8.8.8.8 Set one or more DNS servers to use when addresses are not local. These are open DNS servers.


• local=/example.com/ Our local domain, queries in these domains are answered from /etc/hosts or the static-hosts files.


• address=/doubleclick.net/127.0.0.1 Use this force an address for the specified domains. e.g to block adverts force doubleclck.net to localhost


• no-hosts This options stops dnsmasq using the local /etc/hosts file as a source for lookups .


• addn-hosts=/etc/dnsmasq.d/static/hosts.conf Force dnsmasq to use this file for lookups. It is in the same format as /etc/hosts.


• expand_hosts So we can see our local hosts via our home domain without having to repeatedly specify the domain in our /etc/hosts file.


• domain This is your local domain name. It will tell the DHCP server which host to give out IP addresses for.


• dhcp-range This is the range of IPs that DHCP will serve: 10.20.2.50 to 10.20.2.150, with a lease time of 12 hours. The lease time is how long that IP will be linked to a host.


• dhcp-host=client,10.20.2.10,36h Any machine saying they are hostname = ‘client’ gets this IP address


• dhcp-option=option:router,10.20.2.1 When a host is requesting an IP address via DHCP also tell it the gateway to use.


• dhcp-option=option:ntp-server,10.20.2.5 When a host is requesting an IP address via DHCP also tell it the NTP to use.

Install Dnsmasq server and

# yum install dnsmasq*

# yum install syslinux*

Configuration Dnsmasq server as a PXE Boot

Enable configuration directory " conf-dir=/etc/dnsmasq.d "

# vi /etc/dnsmasq.conf

create new pxe.conf file in configuration directory " dnsmasq.d "

# vi /etc/dnsmasq.d/pxe.conf

To Enable TFTP Server by adding this section

tftp-root=/khandwa/lokesh.com/pxeboot     # here "/khandwa/lokesh.com/pxeboot" is path of tftp server

enable-tftp

Dhcp Boot Option

dhcp-boot=pxelinux.0

dhcp-option=vendor:PXEClient,6,2b

dhcp-no-override

dhcp-range=10.20.2.20,proxy

Here i used "proxy" because i have already dhcp server in network if you don't have a dhcp server you can define range of ip
dhcp-range=10.20.2.50,10.20.2.150,12h

set pxe Boot Option

pxe-prompt="Press F8 for boot menu", 3

pxe-service=X86PC, "Boot from local hard disk", 0

pxe-service=X86PC, "Boot from network", pxelinux

Copy syslinux file in tftp server root directory

# mkdir /khandwa/lokesh.com/pxeboot

# cp /usr/share/syslinux/menu.c32 /khandwa/lokesh.com/pxeboot

# cp /usr/share/syslinux/pxelinux.0 /khandwa/lokesh.com/pxeboot

# cp /usr/share/syslinux/chain.c32 /khandwa/lokesh.com/pxeboot

# cp /usr/share/syslinux/memdisk /khandwa/lokesh.com/pxeboot

# cp /usr/share/syslinux/mboot.c32 /khandwa/lokesh.com/pxeboot

Create pxelinux.cfg directory

# mkdir /khandwa/lokesh.com/pxeboot/pxelinux.cfg

Create "default" file for boot menu

# vi /khandwa/lokesh.com/pxeboot/pxelinux.cfg/default

default menu.c32

prompt 0

timeout 300

ONTIMEOUT local

# Menu for Hiren Live Boot

LABEL Hiren # label name of iso

MENU LABEL Hirens BootCD # menu label name 

KERNEL memdisk # kernel for ISO image called memdisk

APPEND iso initrd=hiren10.iso raw # path of iso image, here iso image path /khandwa/lokesh.com/pxeboot/hiren10.iso

Restart Service

# service dnsmasq restart

If you get error after Restart the Service

dnsmasq: failed to create listening socket: Address already in use



check port of dns ( 53 ) & kill it

# netstat -anlp | grep -w LISTEN

Kill this process

# kill -9 1792

Now Again restart service

# service dnsmasq restart

Now go to the client maching and boot form network

Note : enable network boot setting in BIOS