DNS Security FAQ

Frequently asked questions about DNS security and best practices

DNS Security FAQ

This guide covers common questions about DNS security, encryption protocols, and best practices for securing your DNS queries.

DNS Security Basics

What makes DNS insecure?

Traditional DNS (port 53) sends queries in plain text, making them vulnerable to:

• Eavesdropping: ISPs and network operators can see all DNS queries
• Manipulation: DNS responses can be altered by attackers
• Spoofing: Fake DNS responses can redirect users to malicious sites
• Tracking: DNS queries can be used to track browsing habits

What are encrypted DNS protocols?

DNS over HTTPS (DoH):

• Encrypts DNS queries using HTTPS
• Uses port 443 (same as web traffic)
• Provides confidentiality and integrity
• Supported by major browsers and operating systems

DNS over TLS (DoT):

• Encrypts DNS queries using TLS
• Uses port 853
• Provides end-to-end encryption
• Supported by most DNS clients

DNS over QUIC (DoQ):

• Uses QUIC protocol for encryption
• Potentially faster than DoH/DoT
• Uses port 784
• Limited client support currently

Using Encrypted DNS

How do I enable DoH in browsers?

Firefox:

1. Go to about:config
2. Search for network.trr.mode
3. Set value to 2 (for fallback) or 3 (TRR only)
4. Set network.trr.uri to https://dns.hixbe.com/dns-query

Chrome/Chromium:

# Launch with DoH enabled
chromium --enable-features="dns-over-https" --dns-over-https-server="https://dns.hixbe.com/dns-query"

Edge:

1. Go to Settings → Privacy, search, and services
2. Scroll to Security
3. Choose a DNS service provider or enter custom DoH server

How do I configure DoT on different platforms?

Linux (systemd-resolved):

# Edit /etc/systemd/resolved.conf
[Resolve]
DNS=1.1.1.1#dns.hixbe.com
DNSOverTLS=yes

Windows:

1. Go to Settings → Network & Internet → Wi-Fi/Ethernet
2. Click on your network → Edit DNS settings
3. Select Manual → Enable DNS over HTTPS
4. Enter: https://dns.hixbe.com/dns-query

macOS:

1. Go to System Settings → Network → [Your Network]
2. Click Advanced → DNS → DNS Servers
3. Add DNS server with DoT: 1.1.1.1 (DoT enabled automatically)

What about mobile devices?

Android:

1. Go to Settings → Network & internet → Advanced → Private DNS
2. Select “Private DNS provider hostname”
3. Enter: dns.hixbe.com

iOS:

1. Go to Settings → Wi-Fi → [Network Name]
2. Configure DNS → Manual
3. Add DNS server: 1.1.1.1
4. DNS over TLS will be enabled automatically

DNS Filtering and Security

What is DNS-based content filtering?

DNS filtering blocks access to malicious or unwanted domains by:

• Malware Blocking: Prevents access to known malware distribution sites
• Phishing Protection: Blocks known phishing domains
• Adult Content Filtering: Blocks adult/pornographic content
• Gambling Restrictions: Blocks online gambling sites

How does DNS filtering work?

1. Query Interception: DNS queries are intercepted before resolution
2. Blocklist Checking: Domain is checked against blocklists
3. Response Modification: If blocked, returns NXDOMAIN or blocked page
4. Logging: Blocked attempts are logged for analysis

What are the limitations of DNS filtering?

• Only Domain-Based: Cannot filter content within allowed domains
• Bypassable: Can be circumvented using VPNs or alternative DNS
• False Positives: Legitimate sites may be incorrectly blocked
• No Content Inspection: Cannot analyze actual web content

Best Practices

For Personal Use

1. Use Encrypted DNS: Always prefer DoH or DoT over plain DNS
2. Enable DNSSEC: Validate DNS responses cryptographically
3. Use Filtering: Enable malware blocking at minimum
4. Regular Updates: Keep DNS configurations current

For Organizations

1. Implement DNS Policies: Use different filtering levels for different users
2. Monitor DNS Traffic: Log and analyze DNS queries for threats
3. Use Local DNS: Deploy internal DNS servers with external forwarding
4. Multi-Layer Security: Combine DNS security with other security measures

For Developers

1. Handle DNS Errors: Properly handle NXDOMAIN and other DNS errors
2. Implement Timeouts: Set reasonable timeouts for DNS queries
3. Use DNS Libraries: Prefer libraries that support encrypted DNS
4. Monitor Resolution: Track DNS query performance and failures

Troubleshooting Encrypted DNS

DoH not working

Check browser settings:

• Verify DoH server URL is correct
• Ensure HTTPS interception is disabled
• Check for conflicting extensions

Network issues:

# Test DoH connectivity
curl -I https://dns.hixbe.com/dns-query

DoT connection failures

Check port availability:

# Test DoT port
telnet dns.hixbe.com 853

Firewall configuration:

# Linux - allow DoT
sudo ufw allow 853/tcp

Certificate issues

Certificate validation:

# Check certificate
openssl s_client -connect dns.hixbe.com:853 -servername dns.hixbe.com

Time synchronization:

• Ensure system clock is accurate
• Use NTP servers for time synchronization

Performance Considerations

Does encrypted DNS slow things down?

• Minimal Impact: Modern encryption has negligible performance cost
• Caching Benefits: Encrypted DNS still benefits from caching
• Connection Reuse: TLS connections are reused for efficiency

Speed comparison

Protocol	Typical Latency	Security
Plain DNS	20-50ms	None
DoH	30-70ms	High
DoT	25-60ms	High
DoQ	20-50ms	High

Privacy and Legal Considerations

What data is logged?

Our DNS service may log:

• Query Timestamps: When queries were made
• Client IPs: Source IP addresses (temporarily)
• Query Types: Type of DNS records requested
• Response Codes: Success/failure status

Data retention

• Temporary Logs: Used for debugging and performance monitoring
• Anonymization: IPs are anonymized after 24 hours
• No Content Storage: Actual DNS responses are not stored
• Compliance: Follows privacy regulations and best practices

Legal compliance

• GDPR Compliant: EU data protection regulations
• No Tracking: DNS queries are not used for advertising
• Transparency: Logging practices are documented
• User Control: Users can opt-out of logging

Advanced Configuration

Custom DNS servers

For advanced users, you can set up custom DNS configurations:

# Linux - custom resolv.conf
# /etc/resolv.conf
nameserver 1.1.1.1
nameserver 1.0.0.1
options edns0

# With custom options
options timeout:2 attempts:3 rotate

DNSSEC validation

Enable DNSSEC for cryptographic validation:

# Linux
# /etc/systemd/resolved.conf
DNSSEC=yes

# Test DNSSEC
dig @1.1.1.1 example.com +dnssec

Common Myths

Myth: Encrypted DNS is only for privacy

Reality: While privacy is important, encrypted DNS also provides:

• Protection against DNS spoofing
• Prevention of DNS hijacking
• Secure DNS in public Wi-Fi
• Compliance with security policies

Myth: DNS filtering blocks everything

Reality: DNS filtering is one layer of security that should be combined with:

• Web filtering
• Endpoint protection
• User education
• Network segmentation

Myth: Encrypted DNS is complex to set up

Reality: Modern operating systems and browsers make it easy:

• One-click enable in browsers
• Simple configuration in OS settings
• Automatic detection and setup

Support

For DNS security questions:

• Email: [e-mail]
• Documentation: Check our DNS Service documentation
• Status: Monitor service status at https://status.hixbe.com
• Community: Join discussions in our developer forum

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DNS Privacy

ICANN DNS Privacy Guidelines

DNSSEC

DNS Security Extensions

Encrypted DNS

Cloudflare DNS Encryption Guide

DNS Filtering

Content Filtering Best Practices