DNS blocking is a technique used to prevent access to specific websites or domains by redirecting their requests to a different address. Here are the key points:

1. How DNS Blocking Works:
   • When you type a website address (e.g., “www.example.com”) into your browser, your device queries a DNS server to translate that domain name into an IP address.
   • DNS blocking intercepts these requests and either:
     • Redirects them to a harmless IP address (such as a local server), effectively blocking access to the original site.
     • Returns an error message, preventing the connection altogether.
2. Pros of DNS Blocking:
   • Content Filtering: Blocks access to harmful or inappropriate content (e.g., adult sites, phishing domains).
   • Privacy Enhancement: Prevents tracking by blocking requests to known tracking domains.
   • Malware Prevention: Can stop connections to malicious sites distributing malware.
3. Cons of DNS Blocking:
   • False Positives: Some legitimate sites may be accidentally blocked due to shared domains or overzealous blocklists.
   • Limited Protection: DNS blocking is just one layer of security; it doesn’t replace other measures like firewalls or antivirus software.
4. Choosing a DNS Service:
   • OpenDNS: Offers customizable filtering options for different user profiles (e.g., family-friendly, moderate, high).
   • Cloudflare: Provides fast and secure DNS with optional filtering features.
   • Pi-hole: A self-hosted DNS server that blocks ads and trackers network-wide.
5. Customization:
   • Customize blocklists based on your family’s needs. For example, you can add specific domains to block or whitelist.
   • Regularly review and update blocklists to stay effective.

Remember that while DNS blocking is useful, it should be part of a comprehensive security strategy alongside firewalls, antivirus software, and safe browsing practices.

Setting up DNS blocking on my home network

1. Router-Based DNS Blocking:
   • Find Your Router’s IP Address:
     • Open the Command Prompt (Windows) or System Preferences > Network (Mac).
     • Type ipconfig (Windows) or check the router IP under “Ethernet” (Mac).
   • Access Your Router’s Backend:
     • Enter the router IP address in your browser and log in (use details from the router case).
   • Navigate to Content Filtering:
     • Look for sections like “Basic Rules,” “Firewall,” or “Content.”
     • Find the URL content filter.
   • Add Websites to Blacklist:
     • Add the URLs of websites you want to block to the blacklist or content filter.

2. Using DNS Services (e.g., OpenDNS):
   • NextDNS:
     • Install the NextDNS app on your devices.
     • It combines an encrypted VPN tunnel with DNS blocking and filtering.
     • Blocks malicious sites, ads, and more based on blocklists.
   • OpenDNS Family Shield:
     • Create a free account.
     • Use the IP addresses 208.67.222.123 or 208.67.220.123 in your router’s DNS settings.
     • It blocks specific websites and content.

Remember, DNS blocking complements other security measures, so consider using it alongside firewalls and antivirus software for comprehensive protection.

Risks of using public DNS services

When considering public DNS services, it’s essential to weigh the pros and cons. Let’s explore the risks:

1. Reliability Concerns:
   • Downtime: Free DNS servers may not be as reliable as ISP servers, leading to occasional downtime.
   • Limited Support: Free DNS services typically provide limited customer support compared to ISP counterparts.
2. Security Risks:
   • Data Collection: Some public DNS providers collect user data for various purposes.
   • Vulnerabilities: Public DNS servers are vulnerable to attacks due to their open, distributed design.
   • DNS Spoofing: Malicious actors can manipulate DNS responses, redirecting users to fake sites.
3. Lack of Customization:
   • Public DNS services may lack advanced customization options compared to private DNS setups.

In summary, while free DNS servers can provide speed, security enhancements, and privacy benefits, users must weigh these advantages against potential downsides such as reliability issues, security risks, and limited support.