DoH Security Best Practices

This document provides security best practice recommendations when using DNS over HTTPS.

Basic Security Configuration

Choose Trusted DoH Servers

  1. Verify Server Identity

    • Use servers with DNSSEC support
    • Check server SSL certificates
    • Verify server ownership

  2. Evaluate Privacy Policy

    • Understand data collection policies
    • Check data retention periods
    • Confirm data sharing policies

  3. Consider Geographic Location

    • Choose local servers
    • Avoid cross-border data transmission
    • Consider legal compliance

Enable DNSSEC

  1. Configure DNSSEC Validation

    # Enable DNSSEC on Linux systems
sudo nano /etc/systemd/resolved.conf

[Resolve]
DNSSEC=yes

  2. Verify DNSSEC Status

    # Verify using dig command
dig +dnssec example.com

Advanced Security Configuration

Use ESNI

  1. Configure ESNI Support

    • Use browsers with ESNI support
    • Enable TLS 1.3
    • Configure ESNI keys

  2. Verify ESNI Status

    # Test using curl
curl -v --esni example.com

Prevent DNS Leaks

  1. System-level Configuration

    • Disable traditional DNS
    • Configure firewall rules
    • Use VPN or proxy

  2. Browser Configuration

    • Enable DoH
    • Disable WebRTC
    • Use privacy mode

Enterprise Security Practices

Network Segmentation

  1. Divide Network Zones

    • Management network
    • User network
    • Guest network

  2. Configure Access Control

    # Configure firewall rules
iptables -A OUTPUT -p tcp --dport 53 -j DROP
iptables -A OUTPUT -p udp --dport 53 -j DROP

Monitoring and Logging

  1. Configure Logging

    # Configure DNS logging
sudo nano /etc/dnscrypt-proxy/dnscrypt-proxy.toml

[logging]
log_level = 2
log_file = '/var/log/dnscrypt-proxy.log'

  2. Set Up Alerts

    • Monitor DNS query failures
    • Monitor abnormal traffic
    • Set up security event notifications

Security Auditing

Regular Checks

  1. System Checks

    # Check DNS configuration
cat /etc/resolv.conf

# Check DNS service status
systemctl status systemd-resolved

  2. Security Scanning

    • Use security scanning tools
    • Check for vulnerabilities
    • Update security patches

Compliance Checks

  1. Data Protection

    • Check data encryption
    • Verify access control
    • Review logging

  2. Policy Compliance

    • Check privacy policies
    • Verify data protection
    • Review security measures

Emergency Response

Incident Handling

  1. Detect Incidents

    • Monitor abnormal activities
    • Analyze log data
    • Identify security threats

  2. Response Process

    • Isolate affected systems
    • Collect evidence
    • Fix vulnerabilities

Recovery Plan

  1. Backup Strategy

    • Regular configuration backups
    • Save log data
    • Maintain recovery documentation

  2. Recovery Steps

    • Verify backup integrity
    • Restore system configuration
    • Update security measures

Monitoring Tools

  1. DNS Monitoring

    • DNSWatch
    • DNSLeakTest
    • DNSViz

  2. Security Scanning

    • Nmap
    • Wireshark
    • tcpdump

Protection Tools

  1. Firewall

    • UFW
    • iptables
    • pfSense

  2. Intrusion Detection

    • Snort
    • Suricata
    • Zeek

Next Steps