Debian and Ubuntu DDNS with Bind9 and DHCP

This tutorial is a continuation of my previous post How to setup a LAN DNS server using Bind9 under Debian and Ubuntu Linux which covers the installation of bind9 on a Debian/Ubuntu system. This new tutorial will cover the Dynamic DNS features of bind9.

I assume that you have a running DNS server and configured based on this tutorial.

First we will change the owner of /var/cache/bind to user:bind and group:bind.

We will update the file /etc/bind/named.conf.local and make some few changes. The changes that have been added to the file are highlighted in bold.

//
// Do any local configuration here
//

// Consider adding the 1918 zones here, if they are not used in your
// organization
//include "/etc/bind/zones.rfc1918";

include "/etc/bind/rndc.key";

controls {
        inet 127.0.0.1 allow { localhost; } keys { "rndc-key"; };
};

zone "debian.lan" {
        type master;
        file "db.debian.lan";
        allow-update { key "rndc-key"; };
};

zone "100.168.192.in-addr.arpa" {
        type master;
        file "db.192.168.100";
        allow-update { key "rndc-key"; };
};

Install and configure dhcp3-server

Configure which interface the dhcpd server should listen to. I this case, I assume that our LAN interface is "eth1".

# Defaults for dhcp initscript
# sourced by /etc/init.d/dhcp
# installed at /etc/default/dhcp3-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="eth1"

Then we will configure the dhcp configuration file, create a backup of the file /etc/dhcp3/dhcpd.conf and edit it.

Make sure the configuration file should be exactly the same like this:

ddns-update-style       interim;
ignore                  client-updates;

include "/etc/bind/rndc.key";

zone debian.lan. {
        primary 127.0.0.1;
        key     "rndc-key";
}

authoritative;
subnet 192.168.100.0 netmask 255.255.255.0 {
        range                           192.168.100.2 192.168.100.3;
        option domain-name-servers      192.168.100.1;
        option domain-name              "debian.lan";
        option routers                  192.168.100.1;
        default-lease-time              600;
        max-lease-time                  7200;

        zone main.debian.lan. {
                primary 192.168.100.1;
                key "rndc-key";
        }

        zone 100.168.192.in-addr.arpa. {
                primary 192.168.100.1;
                key "rndc-key";
        }
}

Restart the DNS server and the DHCP server.

Your DDNS server should be ok. Now, if your client in your LAN is Ubuntu, you need to edit the file /etc/dhcp3/dhclient.conf.

Add the following information

send host-name "pc-name";

and run this command to renew your ip address and domain name.

If you are using Fedora, CentOS or RHEL, edit the file

append the hostname

DHCP_HOSTNAME=centos

and restart the network service.
Test your client domain name using dig or nslookup command:

the command will return the following message:

Server:		192.168.100.1
Address:	192.168.100.1#53

Name:	ubuntu01.debian.lan
Address: 192.168.100.2

Check the reverse dns

the command will return the following message:

Server:		192.168.100.1
Address:	192.168.100.1#53

2.100.168.192.in-addr.arpa	name = ubuntu01.debian.lan.

Have fun!