AdGuard employs a comprehensive DNS filtering strategy to block traffic and prevent ads from reaching users. Here's an organized summary of its DNS filtering rules:

1. Global DNS Blocks: AdGuard uses global DNS blocks, such as ".../," to completely stop traffic from accessing the internet, though this is typically reserved for critical services like emergency services.
2. IP Address Filtering: The system includes specific IP addresses that are blocked, such as "169.254.254.254" and "169.254.254.255," to restrict access to certain subnets.
3. Domain Filtering: AdGuard blocks specific domains like "www.example.com" and "www.something.com" to prevent users from accessing these sites.
4. Port Filtering: Rules are set to block specific ports, including 8 and 443, which are critical for HTTP and HTTPS connections.
5. SPF Rules: Simple Perfect Forwarding Service rules are in place to block certain IP addresses from being used for incoming traffic, even if they are not directly used by the server.
6. Domain Blocking: AdGuard includes rules to block specific email domains and user accounts, such as "user@domain.com," to prevent phishing or personal account access.
7. Traffic Filtering: The system may also filter out JavaScript ads and certain types of images to prevent them from reaching users.
8. Combined Filtering: AdGuard employs a combination of these rules to create a robust filter, ensuring that only legitimate traffic and ads are allowed. By using these rules, AdGuard aims to protect against a wide range of threats, ensuring a safer online experience for users.