Knot DNS Installation Guide Installation Guide

Knot DNS is a free and open-source DNS Server. A high-performance authoritative DNS server

Hardware Requirements:

CPU: 2 cores minimum (4+ cores recommended)

RAM: 2GB minimum (4GB+ recommended)

Storage: 1GB for installation

Network: 53 ports

Operating System:

Linux: Any modern distribution (RHEL, Debian, Ubuntu, CentOS, Fedora, Arch, Alpine, openSUSE)

macOS: 10.14+ (Mojave or newer)

Windows: Windows Server 2016+ or Windows 10

FreeBSD: 11.0+

Network Requirements:

Port 53 (default knot-dns port)

Dependencies:

knot-dnsutils, knot-doc

System Access: root or sudo privileges required

This guide supports installation on:

RHEL 8/9 and derivatives (CentOS Stream, Rocky Linux, AlmaLinux)

Debian 11/12

Ubuntu 20.04/22.04/24.04 LTS

Arch Linux (rolling release)

Alpine Linux 3.18+

openSUSE Leap 15.5+ / Tumbleweed

SUSE Linux Enterprise Server (SLES) 15+

macOS 12+ (Monterey and later)

FreeBSD 13+

Windows 10/11/Server 2019+ (where applicable)

bash

# Install EPEL repository if needed
sudo dnf install -y epel-release

# Install knot-dns
sudo dnf install -y knot-dns knot-dnsutils, knot-doc

# Enable and start service
sudo systemctl enable --now knot

# Configure firewall
sudo firewall-cmd --permanent --add-service=knot-dns
sudo firewall-cmd --reload

# Verify installation
knot-dns --version || systemctl status knot

bash

# Update package index
sudo apt update

# Install knot-dns
sudo apt install -y knot-dns knot-dnsutils, knot-doc

# Enable and start service
sudo systemctl enable --now knot

# Configure firewall
sudo ufw allow 53

# Verify installation
knot-dns --version || systemctl status knot

bash

# Install knot-dns
sudo pacman -S knot-dns

# Enable and start service
sudo systemctl enable --now knot

# Verify installation
knot-dns --version || systemctl status knot

bash

# Install knot-dns
apk add --no-cache knot-dns

# Enable and start service
rc-update add knot default
rc-service knot start

# Verify installation
knot-dns --version || rc-service knot status

bash

# Install knot-dns
sudo zypper install -y knot-dns knot-dnsutils, knot-doc

# Enable and start service
sudo systemctl enable --now knot

# Configure firewall
sudo firewall-cmd --permanent --add-service=knot-dns
sudo firewall-cmd --reload

# Verify installation
knot-dns --version || systemctl status knot

bash

# Using Homebrew
brew install knot-dns

# Start service
brew services start knot-dns

# Verify installation
knot-dns --version

bash

# Using pkg
pkg install knot-dns

# Enable in rc.conf
echo 'knot_enable="YES"' >> /etc/rc.conf

# Start service
service knot start

# Verify installation
knot-dns --version || service knot status

powershell

# Using Chocolatey
choco install knot-dns

# Or using Scoop
scoop install knot-dns

# Verify installation
knot-dns --version

bash

# Create configuration directory if needed
sudo mkdir -p /etc/knot

# Set up basic configuration
sudo tee /etc/knot/knot-dns.conf << 'EOF'
# Knot DNS Configuration
server: { udp-workers: 4, tcp-workers: 4 }
EOF

# Test configuration
sudo knot-dns -t || sudo knot configtest

# Reload service
sudo systemctl reload knot

bash

# Set appropriate permissions
sudo chown -R knot-dns:knot-dns /etc/knot
sudo chmod 750 /etc/knot

# Enable security features
# See security section for detailed hardening steps

bash

# Enable service
sudo systemctl enable knot

# Start service
sudo systemctl start knot

# Stop service
sudo systemctl stop knot

# Restart service
sudo systemctl restart knot

# Reload configuration
sudo systemctl reload knot

# Check status
sudo systemctl status knot

# View logs
sudo journalctl -u knot -f

bash

# Enable service
rc-update add knot default

# Start service
rc-service knot start

# Stop service
rc-service knot stop

# Restart service
rc-service knot restart

# Check status
rc-service knot status

bash

# Enable in /etc/rc.conf
echo 'knot_enable="YES"' >> /etc/rc.conf

# Start service
service knot start

# Stop service
service knot stop

# Restart service
service knot restart

# Check status
service knot status

bash

# Using Homebrew services
brew services start knot-dns
brew services stop knot-dns
brew services restart knot-dns

# Check status
brew services list | grep knot-dns

powershell

# Start service
net start knot

# Stop service
net stop knot

# Using PowerShell
Start-Service knot
Stop-Service knot
Restart-Service knot

# Check status
Get-Service knot

bash

# Configure performance settings
cat >> /etc/knot/knot-dns.conf << 'EOF'
server: { udp-workers: 4, tcp-workers: 4 }
EOF

# Apply system tuning
sudo sysctl -w net.core.somaxconn=65535
sudo sysctl -w net.ipv4.tcp_max_syn_backlog=65535

# Restart service
sudo systemctl restart knot

bash

# Configure clustering (if supported)
# See official documentation for cluster setup

# Basic load balancing setup example
# Configure multiple instances on different ports

nginx

upstream knot-dns_backend {
    server 127.0.0.1:53;
    server 127.0.0.1:{default_port}1 backup;
}

server {
    listen 80;
    server_name knot-dns.example.com;
    return 301 https://$server_name$request_uri;
}

server {
    listen 443 ssl http2;
    server_name knot-dns.example.com;

    ssl_certificate /etc/ssl/certs/knot-dns.example.com.crt;
    ssl_certificate_key /etc/ssl/private/knot-dns.example.com.key;

    location / {
        proxy_pass http://knot-dns_backend;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
        
        # WebSocket support (if needed)
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection "upgrade";
    }
}

apache

<VirtualHost *:80>
    ServerName knot-dns.example.com
    Redirect permanent / https://knot-dns.example.com/
</VirtualHost>

<VirtualHost *:443>
    ServerName knot-dns.example.com
    
    SSLEngine on
    SSLCertificateFile /etc/ssl/certs/knot-dns.example.com.crt
    SSLCertificateKeyFile /etc/ssl/private/knot-dns.example.com.key
    
    ProxyRequests Off
    ProxyPreserveHost On
    
    ProxyPass / http://127.0.0.1:53/
    ProxyPassReverse / http://127.0.0.1:53/
    
    # WebSocket support (if needed)
    RewriteEngine on
    RewriteCond %{HTTP:Upgrade} websocket [NC]
    RewriteCond %{HTTP:Connection} upgrade [NC]
    RewriteRule ^/?(.*) "ws://127.0.0.1:53/$1" [P,L]
</VirtualHost>

haproxy

frontend knot-dns_frontend
    bind *:80
    bind *:443 ssl crt /etc/ssl/certs/knot-dns.pem
    redirect scheme https if !{ ssl_fc }
    default_backend knot-dns_backend

backend knot-dns_backend
    balance roundrobin
    option httpchk GET /health
    server knot-dns1 127.0.0.1:53 check
    server knot-dns2 127.0.0.1:{default_port}1 check backup

bash

# Set appropriate permissions
sudo chown -R knot-dns:knot-dns /etc/knot
sudo chmod 750 /etc/knot

# Configure firewall
sudo firewall-cmd --permanent --add-service=knot-dns
sudo firewall-cmd --reload

# Enable SELinux policies (if applicable)
sudo setsebool -P httpd_can_network_connect on

# Configure fail2ban
sudo tee /etc/fail2ban/jail.d/knot-dns.conf << 'EOF'
[knot-dns]
enabled = true
port = 53
filter = knot-dns
logpath = /var/log/knot/*.log
maxretry = 5
bantime = 3600
EOF

bash

# Generate SSL certificates
sudo openssl req -x509 -nodes -days 365 -newkey rsa:2048 \
    -keyout /etc/ssl/private/knot-dns.key \
    -out /etc/ssl/certs/knot-dns.crt

# Configure SSL in knot-dns
# See official documentation for SSL configuration

PostgreSQL Backend (if applicable)

bash

# Create database and user
sudo -u postgres psql << EOF
CREATE DATABASE knot-dns_db;
CREATE USER knot-dns_user WITH ENCRYPTED PASSWORD 'secure_password';
GRANT ALL PRIVILEGES ON DATABASE knot-dns_db TO knot-dns_user;
EOF

# Configure knot-dns to use PostgreSQL
# See official documentation for database configuration

bash

# Create database and user
sudo mysql << EOF
CREATE DATABASE knot-dns_db;
CREATE USER 'knot-dns_user'@'localhost' IDENTIFIED BY 'secure_password';
GRANT ALL PRIVILEGES ON knot-dns_db.* TO 'knot-dns_user'@'localhost';
FLUSH PRIVILEGES;
EOF

bash

# Kernel parameters
sudo tee -a /etc/sysctl.conf << EOF
net.core.somaxconn = 65535
net.ipv4.tcp_max_syn_backlog = 65535
net.ipv4.ip_local_port_range = 1024 65535
net.core.netdev_max_backlog = 5000
vm.swappiness = 10
EOF

sudo sysctl -p

# Knot DNS specific tuning
server: { udp-workers: 4, tcp-workers: 4 }

bash

# Configure system limits
sudo tee -a /etc/security/limits.conf << EOF
knot-dns soft nofile 65535
knot-dns hard nofile 65535
knot-dns soft nproc 32768
knot-dns hard nproc 32768
EOF

yaml

# prometheus.yml configuration
scrape_configs:
  - job_name: 'knot-dns'
    static_configs:
      - targets: ['localhost:53']
    metrics_path: '/metrics'

bash

# Basic health check script
#!/bin/bash
if systemctl is-active --quiet knot; then
    echo "Knot DNS is running"
    exit 0
else
    echo "Knot DNS is not running"
    exit 1
fi

bash

# Configure log rotation
sudo tee /etc/logrotate.d/knot-dns << 'EOF'
/var/log/knot/*.log {
    daily
    rotate 14
    compress
    delaycompress
    missingok
    notifempty
    create 0640 knot-dns knot-dns
    postrotate
        systemctl reload knot > /dev/null 2>&1 || true
    endscript
}
EOF

bash

#!/bin/bash
# Knot DNS backup script
BACKUP_DIR="/backup/knot-dns"
DATE=$(date +%Y%m%d_%H%M%S)

mkdir -p "$BACKUP_DIR"

# Stop service (if required)
systemctl stop knot

# Backup configuration
tar -czf "$BACKUP_DIR/knot-dns-config-$DATE.tar.gz" /etc/knot

# Backup data (adjust paths as needed)
tar -czf "$BACKUP_DIR/knot-dns-data-$DATE.tar.gz" /var/lib/knot-dns

# Start service
systemctl start knot

# Clean old backups (keep 30 days)
find "$BACKUP_DIR" -name "*.tar.gz" -mtime +30 -delete

echo "Backup completed: $BACKUP_DIR"

bash

# Stop service
sudo systemctl stop knot

# Restore configuration
sudo tar -xzf /backup/knot-dns/knot-dns-config-*.tar.gz -C /

# Restore data
sudo tar -xzf /backup/knot-dns/knot-dns-data-*.tar.gz -C /

# Set permissions
sudo chown -R knot-dns:knot-dns /etc/knot
sudo chown -R knot-dns:knot-dns /var/lib/knot-dns

# Start service
sudo systemctl start knot

1. Service won't start:

bash

# Check logs
sudo journalctl -u knot -n 100
sudo tail -f /var/log/knot/*.log

# Check configuration
sudo knot-dns -t || sudo knot configtest

# Check permissions
ls -la /etc/knot
ls -la /var/lib/knot-dns

2. Connection refused:

bash

# Check if service is listening
sudo ss -tlnp | grep 53
sudo netstat -tlnp | grep 53

# Check firewall
sudo firewall-cmd --list-all
sudo iptables -L -n

# Test connection
telnet localhost 53
nc -zv localhost 53

3. Performance issues:

bash

# Check resource usage
top -p $(pgrep knotd)
htop -p $(pgrep knotd)

# Check connections
ss -ant | grep :53 | wc -l

# Monitor I/O
iotop -p $(pgrep knotd)

bash

# Run in debug mode
sudo knot-dns -d
# or
sudo knot debug

# Increase log verbosity
# Edit configuration to enable debug logging

yaml

version: '3.8'
services:
  knot-dns:
    image: knot-dns:latest
    container_name: knot-dns
    ports:
      - "53:53"
    volumes:
      - ./config:/etc/knot
      - ./data:/var/lib/knot-dns
    environment:
      - knot-dns_CONFIG=/etc/knot/knot-dns.conf
    restart: unless-stopped
    networks:
      - knot-dns_net

networks:
  knot-dns_net:
    driver: bridge

yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: knot-dns
spec:
  replicas: 3
  selector:
    matchLabels:
      app: knot-dns
  template:
    metadata:
      labels:
        app: knot-dns
    spec:
      containers:
      - name: knot-dns
        image: knot-dns:latest
        ports:
        - containerPort: 53
        volumeMounts:
        - name: config
          mountPath: /etc/knot
      volumes:
      - name: config
        configMap:
          name: knot-dns-config
---
apiVersion: v1
kind: Service
metadata:
  name: knot-dns
spec:
  selector:
    app: knot-dns
  ports:
  - port: 53
    targetPort: 53
  type: LoadBalancer

yaml

---
- name: Install and configure Knot DNS
  hosts: all
  become: yes
  tasks:
    - name: Install knot-dns
      package:
        name: knot-dns
        state: present
    
    - name: Configure knot-dns
      template:
        src: knot-dns.conf.j2
        dest: /etc/knot/knot-dns.conf
        owner: knot-dns
        group: knot-dns
        mode: '0640'
      notify: restart knot-dns
    
    - name: Start and enable knot-dns
      systemd:
        name: knot
        state: started
        enabled: yes
  
  handlers:
    - name: restart knot-dns
      systemd:
        name: knot
        state: restarted

Maintenance

bash

# RHEL/CentOS/Rocky/AlmaLinux
sudo dnf update knot-dns

# Debian/Ubuntu
sudo apt update && sudo apt upgrade knot-dns

# Arch Linux
sudo pacman -Syu knot-dns

# Alpine Linux
apk update && apk upgrade knot-dns

# openSUSE
sudo zypper update knot-dns

# FreeBSD
pkg update && pkg upgrade knot-dns

# Always backup before updates
tar -czf /backup/knot-dns-pre-update-$(date +%Y%m%d).tar.gz /etc/knot

# Restart after updates
sudo systemctl restart knot

Regular Maintenance Tasks

bash

# Clean logs
find /var/log/knot -name "*.log" -mtime +30 -delete

# Verify integrity
sudo knot-dns --verify || sudo knot check

# Update databases (if applicable)
sudo knot-dns-update-db

# Optimize performance
sudo knot-dns-optimize

# Check for security updates
sudo knot-dns --security-check

Official Documentation: https://docs.knot-dns.org/

GitHub Repository: https://github.com/knot-dns/knot-dns

Community Forum: https://forum.knot-dns.org/

Wiki: https://wiki.knot-dns.org/

Comparison vs BIND, PowerDNS, NSD, Unbound: https://docs.knot-dns.org/comparison

---

Note: This guide is part of the HowToMgr collection. Always refer to official documentation for the most up-to-date information.

1. Prerequisites

2. Supported Operating Systems

3. Installation

RHEL/CentOS/Rocky Linux/AlmaLinux

Debian/Ubuntu

Arch Linux

Alpine Linux

openSUSE/SLES

macOS

FreeBSD

Windows

Initial Configuration

Basic Configuration

Security Hardening

5. Service Management

systemd (RHEL, Debian, Ubuntu, Arch, openSUSE)

OpenRC (Alpine Linux)

rc.d (FreeBSD)

launchd (macOS)

Windows Service Manager

Advanced Configuration

Performance Optimization

Clustering and High Availability

Reverse Proxy Setup

nginx Configuration

Apache Configuration

HAProxy Configuration

Security Configuration

Basic Security Setup

SSL/TLS Configuration

Database Setup

PostgreSQL Backend (if applicable)

MySQL/MariaDB Backend (if applicable)

Performance Optimization

System Tuning

Resource Limits

Monitoring

Prometheus Integration

Health Checks

Log Monitoring

9. Backup and Restore

Backup Script

Restore Procedure

6. Troubleshooting

Common Issues

Debug Mode

Integration Examples

Docker Compose

Kubernetes Deployment

Ansible Playbook

Maintenance

Update Procedures

Regular Maintenance Tasks

Additional Resources

Related Dns servers Guides

BIND Installation Guide

CoreDNS Installation Guide

dnsmasq Installation Guide