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  

 

 

 

 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.