Power Zone

Creating a Master DNS Server

To get your configuration going, you need to install PowerDNS on your primary or master server by modifying the lines shown in Listing 7 in /etc/powerdns/pdns.d/pdns.local.gmysql. Finally, you want to restart your PowerDNS service with:

sudo service pdns restart

With a base PowerDNS configuration and your servers up and running, you can now install your packages and set up your MySQL back end. (Also see the box "Testing the PowerDNS Server.)

#
# MySQL back end configuration
#
launch=gmysql
# Tells our PowerDNS server we are using MySQL backend
config-dir=/etc/powerdns/pdns.d/
# Specifies our configuration file
gmysql-host=127.0.0.1
# Configures the IP address that PowerDNS will listen on gmysql-user=puser
# Our configured PowerDNS username
gmysql-password=pleasepickastrongpassword
# This is our MySQL password. Please, for the love of all that is sacred, stop using weak passwords!
gmysql-dbname=pdns
# This details which MySQL database PowerDNS should use.
local-address=192.168.1.10
# Specifies the local IP for PowerDNS to listen on.
master=yes
# This tells PowerDNS to run this as the primary server. This primary server will send out a special notify packet to notify the secondary or slave of updates.
setgid=pdns
# Sets Group ID to this one for improved security
setuid=pdns
# Sets user id to this for improved security
version-string=Hostfile 0.1 Alpha
# Bogus server version is divulged via dig quiry, such as dig @ns1.example.com -c CH -t txt version.bind. There is no security through obscurity, but there is certainly absurdity... =P

MySQL Database

To begin, simply install MySQL with the command:

primary:~$sudo apt-get install mysql-server mysql-common

As part of the installer, you will be asked to set your MySQL root passwords. Please choose a strong password. Your yet-to-be-configured server needs a bit of tweaking before you can add databases and users, so navigate over to edit /etc/mysql/my.cnf in your favorite text editor. In this case, you are going to change the address to which the MySQL servicer listens on your server localhost:

Bind-address            = 127.0.0.1

Now you can connect to your newly minted MySQL server and begin configuring it:

primary:~$mysql -h localhost -u root -p

Next, create and configure a MySQL database,

create database pdns;

then add a user that will have access to that database:

GRANT ALL ON pdns.* TO 'puser'@'localhost' IDENTIFIED BY 'pleasepickastrongpassword';
GRANT ALL ON pdns.* TO 'puser'@'localhost.localdomain' IDENTIFIED BY 'pleasepickastrongpassword';
FLUSH PRIVILEGES;

Now you can create the database required for your install of PowerDNS (Listing 8). Of course, you can do much more to secure MySQL [5], but for the sake of brevity, I don't include much detail. Like any other application, it needs some extra attention to improve security from its default installed state.

use pdns;
create table domains (
  id              INT auto_increment,
  name            VARCHAR(255) NOT NULL,
  master          VARCHAR(128) DEFAULT NULL,
  last_check      INT DEFAULT NULL,
  type            VARCHAR(6) NOT NULL,
  notified_serial INT DEFAULT NULL,
  account         VARCHAR(40) DEFAULT NULL,
  primary key (id)
) Engine=InnoDB;
CREATE UNIQUE INDEX name_index ON domains(name);
CREATE TABLE records (
  id              INT auto_increment,
  domain_id       INT DEFAULT NULL,
  name            VARCHAR(255) DEFAULT NULL,
  type            VARCHAR(10) DEFAULT NULL,
  content         VARCHAR(64000) DEFAULT NULL,
  ttl             INT DEFAULT NULL,
  prio            INT DEFAULT NULL,
  change_date     INT DEFAULT NULL,
  primary key(id)
) Engine=InnoDB;
CREATE INDEX nametype_index ON records(name,type);
CREATE INDEX domain_id ON records(domain_id);
create table supermasters (
  ip         VARCHAR(64) NOT NULL,
  nameserver VARCHAR(255) NOT NULL,
  account    VARCHAR(40) DEFAULT NULL
) Engine=InnoDB;
quit;

Poweradmin

At this point, you could manage this PowerDNS configuration back end in many ways. Unlike simple text-file-based configuration (the BIND-compatible back end covered in the first part of this article), you would have to use any number of database management tools, bake your own scripts, or use a web administration interface. Generally, if you don't plan to script or code your own solution, going with a web GUI is a good choice. A graphical interface has many benefits: easing administration, encouraging proper syntax, and decreasing syntactic errors.

Poweradmin is an open source, friendly, and easy-to-use web GUI for PowerDNS that supports key features. With this feature-rich web application, you will be managing your DNS environment in no time flat. However, before starting, you need to install it. Like most applications, it has a few prerequisites:

• MySQL or PostgreSQL
• Apache
• PHP
• session, gettext, mcrypt PHP modules
• PEAR, PEAR::MDB2
• GNU gettext

Because a nifty Poweradmin package is lacking, you have to install the prerequisites and then grab the binaries:

primary:~$sudo apt-get install apache2 libapache2-mod-php5 php5 php5-common php5-curl php5-dev php5-gd php-pear php5-imap php5-mcrypt php5-common php5-ming php5-mysql php5-xmlrpc gettext
primary:~$sudo pear install MDB2
primary:~$sudo pear install MDB2_Driver_mysql

Now that you have your prerequisites, you can install the Poweradmin application itself :

primary:~$cd /tmp
primary:~$wget https://github.com/downloads/Poweradmin/Poweradmin/Poweradmin-2.1.6.tgz
primary:~$tar xvfz Poweradmin-2.1.4.tgz
primary:~$mv Poweradmin-2.1.4 /var/www/Poweradmin
primary:~$touch /var/www/Poweradmin/inc/config.inc.php
primary:~$chown -R www-data:www-data /var/www/Poweradmin/

Note that I've only highlighted the steps that might require some user customization. Obvious steps (shown in Figures 1-4) were explicitly excluded. Once you've set up Poweradmin, you can fire up the browser of your choice and connect to http://primary/Poweradmin/install/index.php .

Figure 1: Select your language.

Figure 2: Enter your MySQL information.

Figure 3: Enter your basic DNS domain information.

Figure 4: Instructions on how to grant Poweradmin rights.

For Poweradmin to update data in the tables, you need to give it some limited rights. To do this, you should create a new user and give it rights to select, delete, insert, and update records in the PowerDNS database. After you have added the new user, go back to MySQL and execute:

primary:~$mysql -h localhost -u root -p
use pdns;
GRANT SELECT, INSERT, UPDATE, DELETE
ON pdns.*
TO 'padmin'@'localhost'
IDENTIFIED BY 'pleasepickastrongpassword';
quit;

Once you are finished with the initial setup, you should do one more thing for security's sake,

primary:~$rm -fr /var/www/Poweradmin/install/

which removes the install directory.

Like other PHP-based web applications, Poweradmin has a core configuration file that you can edit and customize to your heart's content in the file /var/www/Poweradmin/inc/config.inc.php. If you want to further customize your config file, you can edit this or explore the rest of this application's subdirectories.