Tag: sudo

By Christopher P Wakefield

Linux MintToday we will have a look at setting up a DNS server on Linux. This tutorial was configured using Linux Mint 9 but the steps are the same for any Linux distribution.

First thing to do is to install the software we need. Open up a terminal and type:

sudo apt-get install bind9

Once installed it is time for some configuring. The first file we need to configure is named.conf.local. So in the terminal type:

sudo nano /etc/bind/named.conf.local

I have used nano to open up the file but use whichever text editor you are happy with. Insert the following code into the file:

# This is the zone definition. replace example.com with your domain name

zone “business.com” {

type master;

file “/etc/bind/zones/business.com.db”;


# This is the zone definition for reverse DNS. replace 0.168.192 with your network address in reverse notation – e.g my network address is 192.168.0

zone “1.168.192.in-addr.arpa” {

type master;

file “/etc/bind/zones/rev.0.168.192.in-addr.arpa”;


Replace business.com with the name of your DNS domain (this is not the same as an active directory domain but rather a name for your DNS zone).

Next up is the options file. In the terminal type:

sudo nano /etc/bind/named.conf.options

Within this file we need to modify the forwarder with the address of your ISP’s DNS servers. So modify the file adding the following:

forwarders {;;


Replace the addresses above with the addresses of your ISP’s DNS servers.

Now we need to add the zones file:

sudo mkdir /etc/bind/zones

And then configure it:

sudo nano /etc/bind/zones/business.com.db (replace business.com with your DNS domain).

Add the following code to the file:

// replace example.com with your domain name. do not forget the. after the domain name!

// Also, replace ns1 with the name of your DNS server

business.com. IN SOA chris-server.business.com.

// Do not modify the following lines!







// Replace the following line as necessary:

// ns1 = DNS Server name

// mta = mail server name

// example.com = domain name

business.com. IN NS chris-server.business.com.

business.com. IN MX 10 mta.example.com.

// Replace the IP address with the right IP addresses.

www IN A

mta IN A

chris-server IN A

In the above code replace the following:

business.com with your DNS domain name, with your static DNS server address,

chris-server.business.com with your computers hostname.dns-domain,

mta is your mail server (if you have one). If you do modify the IP address to show this.

Next we have to create the reverse DNS zone file:

sudo nano /etc/bind/zones/rev.1.168.192.in-addr.arpa

Add the following code:

//replace example.com with yoour domain name, ns1 with your DNS server name.

// The number before IN PTR example.com is the machine address of the DNS server

@ IN SOA chris-server.business.com admin.business.com. (







IN NS chris-server.business.com.

1 IN PTR business.com

All that is left to do is restart bind:

sudo service bind9 restart (using upstart) or sudo /etc/init.d/bind9 restart (init scripts)

Don’t forget to test the new configuration:

dig business.com

Here at ComTech I love Linux. I use it for my own systems in the office and ‘pass on the good word’ to clients when appropriate. I can sort out any Linux queries you might have, including setting up servers, or offer advice if needed. Please go to http://www.comtech247.net/business-it for more information.

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Linux Mint 12 logoBy Christopher P Wakefield

Usually I would set up a Linux dhcp server using the dhcp3-server package. With the arrival of Linux Mint 12 the configuration is slightly different. This tutorial will outline the new steps.

First thing to do is to give your server a static IP address.

Now we need to install the dhcp package. Open up a terminal and type:

sudo apt-get install isc-dhcp-server

There are two main files /etc/default/isc-dhcp-server and /etc/dhcp/dhcpd.conf~ which we will need to configure so lets take the first. Open up a terminal and using your favourite text editor type:

sudo gedit /etc/default/isc-dhcp-server

You should get the following:


# Defaults for dhcp initscript # sourced by /etc/init.d/dhcp # installed at /etc/default/isc-dhcp-server by the maintainer scripts

# # This is a POSIX shell fragment #

# On what interfaces should the DHCP server (dhcpd) serve DHCP requests? # Separate multiple interfaces with spaces, e.g. “eth0 eth1″. INTERFACES=”eth0″


Replace eth0 above with the name of your network interface that you want the server to lease addresses on. Onto the next file. Open up a terminal and type:

sudo gedit /etc/dhcp/dhcdp.conf~

which should give you the output below.


# # Sample configuration file for ISC dhcpd for Debian # # Attention: If /etc/ltsp/dhcpd.conf exists, that will be used as # configuration file instead of this file. # #

# The ddns-updates-style parameter controls whether or not the server will # attempt to do a DNS update when a lease is confirmed. We default to the # behavior of the version 2 packages (‘none’, since DHCP v2 didn’t # have support for DDNS.) ddns-update-style none;

# option definitions common to all supported networks… option domain-name “example.org”; option domain-name-servers ns1.example.org, ns2.example.org;

option domain-name “business.com”; default-lease-time 600; max-lease-time 7200;

# If this DHCP server is the official DHCP server for the local # network, the authoritative directive should be uncommented. #authoritative;

# Use this to send dhcp log messages to a different log file (you also # have to hack syslog.conf to complete the redirection). log-facility local7;

# No service will be given on this subnet, but declaring it helps the # DHCP server to understand the network topology.

#subnet netmask { #}

# This is a very basic subnet declaration.

subnet netmask { range; option routers; option subnet-mask;

option broadcast-address; option domain-name-servers,;

option ntp-servers; option netbios-name-servers; option netbios-node-type 8; }

option routers rtr-239-0-1.example.org, rtr-239-0-2.example.org;


# This declaration allows BOOTP clients to get dynamic addresses, # which we don’t really recommend.

#subnet netmask { # range dynamic-bootp; # option broadcast-address; # option routers rtr-239-32-1.example.org; #}

# A slightly different configuration for an internal subnet. #subnet netmask { # range; # option domain-name-servers ns1.internal.example.org; # option domain-name “internal.example.org”; # option routers; # option broadcast-address; # default-lease-time 600; # max-lease-time 7200; #}

# Hosts which require special configuration options can be listed in # host statements. If no address is specified, the address will be # allocated dynamically (if possible), but the host-specific information # will still come from the host declaration.

#host passacaglia { # hardware ethernet 0:0:c0:5d:bd:95; # filename “vmunix.passacaglia”; # server-name “toccata.fugue.com”; #}

# Fixed IP addresses can also be specified for hosts. These addresses # should not also be listed as being available for dynamic assignment. # Hosts for which fixed IP addresses have been specified can boot using # BOOTP or DHCP. Hosts for which no fixed address is specified can only # be booted with DHCP, unless there is an address range on the subnet # to which a BOOTP client is connected which has the dynamic-bootp flag # set. #host fantasia { # hardware ethernet 08:00:07:26:c0:a5; # fixed-address fantasia.fugue.com; #}

# You can declare a class of clients and then do address allocation # based on that. The example below shows a case where all clients # in a certain class get addresses on the 10.17.224/24 subnet, and all # other clients get addresses on the 10.0.29/24 subnet.

#class “foo” { # match if substring (option vendor-class-identifier, 0, 4) = “SUNW”; #}

#shared-network 224-29 { # subnet netmask { # option routers rtr-224.example.org; # } # subnet netmask { # option routers rtr-29.example.org; # } # pool { # allow members of “foo”; # range; # } # pool { # deny members of “foo”; # range; # } #}


This needs a little bit of explaining.

1. Everything in bold needs adding to the file. Adjust your settings according to your network requirements.

2. The option domain name is your dns zone name. For example set to business.com.

3. Range should be the range of ip addresses that you want the server to give out to clients.

Now restart the dhcp service by typing:

sudo service isc-dhcp-server restart

That’s it!! Your dhcp server should be running, however it is best to check. Open up a terminal and type:

sudo netstat -uap

which will show you the following information:


Active Internet connections (servers and established)

Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name

udp 0 0 *:55827 *:* 916/avahi-daemon: r udp 0 0 chris-desktop.lo:domain *:* 1273/named udp 0 0 chris-desktop:domain *:* 1273/named udp 0 0 *:bootps *:* 4525/dhcpd udp 0 0 *:17500 *:* 1768/dropbox udp 0 0 *:54407 *:* 4539/VirtualBox udp 0 0 *:* 1016/nmbd udp 0 0 chris-deskto:netbios-ns *:* 1016/nmbd udp 0 0 *:netbios-ns *:* 1016/nmbd udp 0 0 *:* 1016/nmbd udp 0 0 chris-deskt:netbios-dgm *:* 1016/nmbd udp 0 0 *:netbios-dgm *:* 1016/nmbd udp 0 0 *:mdns *:* 916/avahi-daemon: r udp6 0 0 [::]:domain [::]:* 1273/named udp6 0 0 [::]:51853 [::]:* 916/avahi-daemon: r udp6 0 0 [::]:mdns [::]:* 916/avahi-daemon: r


This shows that the dhcp daemon is working.

Hi I am Chris the owner of ComTech. I provide IT support to both personal and business clients from my base in Alloa, Clacknmannanshire. Here at ComTech I am experienced in using Windows and Linux technologies whether it be for the home or business. I also incorporate Blackberry hardware into my business, namely the Blackberry Playbook and Bold 9780. I can advise, design and implement solutions to any problems you may have so if you have IT issues just pick up the phone. Please go to http://www.comtech247.net for more information.

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