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DNS Hosting Platform Using PowerDNS

The sdnog DNS-control platform is designed for high availability and reliability of DNS zones. It consists of a hidden master DNS server and two publicly visible secondary DNS servers, all running PowerDNS. This structure ensures secure DNS management and effective load distribution

Structure 

1. Hidden Master DNS Server

  • Role: Manages DNS zone files and makes updates. This server is not publicly accessible.
  • Software: PowerDNS Authoritative Server
  • Responsibilities: Primary source for DNS data, handles updates, and replicates changes to secondary servers.
  • Access: Users do not interact with this server directly. Zone management is done through the PowerDNS web GUI https://dnscontrol.sdnog.sd/login

2. Public Secondary DNS Servers

  • Role: Serve DNS records to the public, providing redundancy and load balancing.
  • Software: PowerDNS Authoritative Server
  • Responsibilities: Retrieve and serve DNS data from the master server.

DNS Names: ns1.hosting.sdnog.sd and ns2.hosting.sdnog.sd 


  • sdnog DNS control Platform .png

    User Interaction

    Users need to contact their Domain provider (eg. for .sd domains contact Sudan Internet Society) to map their domain’s NS records to the sdnog public secondary servers (ns1.hosting.sdnog.sd and ns2.hosting.sdnog.sd ) They will manage their DNS zones using the PowerDNS web GUI provided by the hidden master server. Changes made in the master server are automatically replicated to the secondary servers.

    Prerequisites

    Three servers with PowerDNS installed: one hidden master and two public secondaries. Proper network configuration and access controls. Basic understanding of DNS and PowerDNS configuration.

    Installation

    1. Install PowerDNS on All Servers

    On each server (master and secondaries), install PowerDNS Authoritative Server. This example uses a Debian-based system:

     
 sudo apt update
 sudo apt install pdns-server pdns-backend-mysql

    follow this page to setup DB: https://www.digitalocean.com/community/tutorials/how-to-install-and-configure-powerdns-with-a-mariadb-backend-on-ubuntu-14-04

    2. Configure the Hidden Master DNS Server

    Edit the PowerDNS Configuration File

    Open /etc/powerdns/pdns.conf and configure the following parameters:

     master=yes
 allow-axfr-ips=IP_OF_SECONDARY1,IP_OF_SECONDARY2
 webserver=yes
 webserver-address=127.0.0.1
 webserver-port=8081

    Replace IP_OF_SECONDARY1 and IP_OF_SECONDARY2 with the IP addresses of the secondary servers. Ensure the web server is only accessible from internal IPs or localhost.

    Set Up the Database

    Configure the database connection in /etc/powerdns/pdns.conf. For mysql:

    mysql -u powerdns_user -p USE powerdns;

    Next we will crate a new row in the supermasters table. This row will specify the master server IP address, and the Fully Qualified Domain Name (FQDN) of the slave server we are currently configuring.

    insert into supermasters values ('111.111.111.111', 'ns2.example-dns.com', 'admin');

    Add DNS Zones

    Use the PowerDNS web GUI or pdnsutil tool to add and manage DNS zones:

     pdnsutil create-zone example.com
 pdnsutil add-record example.com www A 192.0.2.1

    Restart PowerDNS

    sudo systemctl restart pdns

    3. Configure the Public Secondary DNS Servers

    Edit the PowerDNS Configuration File

    On each secondary server, open /etc/powerdns/pdns.conf and configure:

    master=no

    Set Up Zone Transfers

    Configure the secondary servers to request zone transfers from the master server:

    notify-axfr-ips=MASTER_IP

    Replace MASTER_IP with the IP address of the hidden master server.

    Reload DNS Zones

    Use the pdnsutil tool to add the zones as secondary:

    pdnsutil add-zone example.com ns1.hosting.sdnog.sd

    Restart PowerDNS

    sudo systemctl restart pdns

    4. Update NS Records

    Contact your Domain provider (eg.the Sudan Internet Society) to map your domain’s NS records to: ns1.hosting.sdnog.sd ns2.hosting.sdnog.sd.

    5. Verify the Configuration

    Test DNS resolution and replication using tools like dig:

    dig @ns1.hosting.sdnog.sd example.com
dig @ns2.hosting.sdnog.sd example.com

    Ensure that updates on the master are correctly replicated to the secondary servers.

    Troubleshooting
    • Check Logs: Review logs in /var/log/syslog or /var/log/pdns.log for errors.
    • Verify Connectivity: Ensure all servers communicate properly and that firewalls are correctly configured.
    • Zone Transfer Issues: Confirm that allow-axfr-ips and notify-axfr-ips are set correctly.
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