DNS tracking works by monitoring DNS queries and comparing the returned IP addresses against predefined criteria. Here's a breakdown:
DNS Tracking Process
The core function of DNS tracking is to ensure that a domain name resolves to the correct IP address. This process involves the following:
- DNS Query: When you try to access a website (e.g., www.example.com), your computer sends a DNS query to a DNS server. This query asks for the IP address associated with that domain name.
- IP Address Retrieval: The DNS server responds with the corresponding IP address.
- Comparison: The DNS tracking system takes the IP address from the DNS query and compares it to a list of expected IP addresses. This list can use individual IP addresses or regular expressions for flexibility.
- Alerting: If the retrieved IP address does not match the expected values, the tracking system will trigger an alert.
Example Scenario
Imagine you expect www.example.com to always resolve to 192.168.1.100.
- Normal Operation: When a DNS query for
www.example.comreturns192.168.1.100, everything is fine. - Tracking Failure: If the query returns
192.168.1.150instead, the DNS tracker detects a discrepancy and alerts you.
Practical Applications of DNS Tracking
DNS tracking has several practical applications, including:
- Detecting DNS Hijacking: When malicious actors redirect a domain name to their IP address, DNS tracking can immediately notify you.
- Monitoring CDN Changes: If you use a Content Delivery Network (CDN), changes to the CDN's IP address range can be tracked.
- Ensuring Website Availability: By monitoring DNS records, you can ensure that your website is reachable via the correct IP address.
- Tracking DNS Propagation: After a DNS change, you can track whether the changes have propagated successfully across the DNS network.
Key Aspects of DNS Tracking
| Aspect | Description |
|---|---|
| Queries | The initial request for an IP address corresponding to a domain name. |
| IP Address | The numeric address (e.g., 192.168.1.100) that devices use to locate websites on the Internet. |
| Comparison | The act of matching the retrieved IP against predefined expectations. |
| Alerting | The action that occurs when a discrepancy is detected. |
Using Regular Expressions
Regular expressions are a powerful tool in DNS tracking. They allow for the tracking of changes that may involve multiple IP addresses or patterns. For example:
- A regular expression like
192\.168\.1\.\d+will match any IP address in the range of192.168.1.0to192.168.1.255. This allows you to be flexible with allowed IP ranges. - The use of regular expressions offers a dynamic method to compare the DNS resolved IP addresses that provide more flexibility than comparing against one static IP.
