DNS Probe Configuration in Proberix

This guide explains how to configure DNS probes in Proberix to monitor the availability and correctness of DNS records. DNS probes help verify that your domain name system is resolving as expected and alert you to issues like missing or altered records.

Required Configuration

When setting up a DNS probe, the following fields are mandatory:

Domain to Query:
The domain name you want to query. This could be your root domain (e.g., example.com) or a subdomain (e.g., api.example.com).

Record Type:
The type of DNS record to query. Supported values include:

• A — IPv4 address
• AAAA — IPv6 address
• CNAME — Canonical name
• MX — Mail exchange server
• TXT — Text record
• NS — Name server
• PTR — Reverse lookup

Optional Configuration

DNS Resolver:
By default, Proberix uses the system's default DNS resolver. You can optionally specify a custom DNS server (e.g., 8.8.8.8) to route the query through a specific upstream resolver.

Response Validation:
Specify expected values for resolved DNS records. This helps detect propagation issues, unauthorized changes, or mismatches in DNS responses. You can use the Fetch Current Value button to pull the latest live result and set it as a baseline pattern for validation.

For full details, see the Response Validation documentation.

Enable Change Detection:
When enabled, the probe tracks changes in the resolved DNS records over time. This is useful for detecting unintended updates, propagation issues, or unauthorized modifications to DNS configurations.

For details on how change tracking works, refer to Change Detection Documentation.

Monitoring Process

A DNS probe in Proberix follows these steps:

1. Initializes a DNS resolver (optionally using the configured custom DNS server).
2. Sends a DNS query for the specified record and type.
3. Receives and serializes the response.
4. If response validation is configured, the probe checks whether the response matches the defined expectations.
5. Returns a result indicating:
   • "ok" — Successful query and match
   • "mismatch" — Record resolved but didn’t match expectations
   • "error" — DNS query failed (e.g., not found, timeout, malformed)

All DNS responses are available for inspection in the Proberix dashboard for 7 days, while probe statistics such as resolution time and status are retained for 6 months.

Best Practices

• Use response validation to catch unexpected DNS changes, such as DNS hijacking or propagation delays.
• Monitor mission-critical records like A, CNAME, and MX to ensure continuous email and web service availability.
• Reverse DNS (PTR) checks are especially useful when monitoring outbound IP reputation or validating mail server configurations.

Advanced Considerations

DNS probes in Proberix are read-only and lightweight. They are designed for integrity monitoring, not high-frequency DNS stress testing. Because DNS propagation and TTL values can cause temporary inconsistencies across different resolvers, short-lived mismatches may occur even if the records are correctly configured. This is especially common shortly after making DNS changes, as it can take time for updates to fully propagate throughout the internet.

DNS probes complement other network and application probes by verifying the foundational layer of domain resolution that supports all internet-based services.