DNS Health Check

A DNS Health Check is a comprehensive analysis of your domain's DNS configuration to identify potential issues, misconfigurations, and security vulnerabilities. This page explains what DNS health checks are, why they're important, and how to use our DNS Health Check tool.

What is a DNS Health Check?

A DNS Health Check is a diagnostic process that evaluates various aspects of your domain's DNS configuration to ensure it's properly set up, secure, and optimized for performance. It examines DNS records, nameserver configuration, delegation settings, and other critical DNS components.

Think of it as a comprehensive check-up for your domain's DNS infrastructure, similar to how you might get a health check-up from a doctor to identify potential issues before they become serious problems.

Why DNS Health Matters

DNS is a critical component of your online presence. Problems with your DNS configuration can lead to:

Website Downtime: Incorrect DNS settings can make your website inaccessible to users.
Email Delivery Issues: Misconfigured MX records or missing SPF/DKIM/DMARC records can affect email deliverability.
Security Vulnerabilities: Improperly configured DNS can expose your domain to attacks like DNS spoofing or cache poisoning.
Poor Performance: Suboptimal DNS configuration can lead to slow website loading times and poor user experience.
SEO Impact: DNS issues can affect search engine crawling and indexing, potentially harming your search rankings.

Regular DNS health checks help you identify and address these issues before they impact your users or business.

What a DNS Health Check Examines

Our DNS Health Check tool examines multiple aspects of your domain's DNS configuration:

Nameserver Configuration

Verifies that your domain has at least two nameservers (for redundancy)
Checks that nameservers are responding correctly
Ensures nameservers are properly delegated
Verifies that nameservers are on different networks (for better reliability)

DNS Records Verification

Checks for essential DNS records (A, AAAA, MX, etc.)
Verifies that records are properly formatted
Ensures consistency across all authoritative nameservers
Identifies missing or conflicting records

Email Configuration

Validates MX records for proper email routing
Checks for SPF, DKIM, and DMARC records for email authentication
Ensures proper configuration of email security records
Identifies potential email deliverability issues

Security Assessment

Checks for DNSSEC implementation and validation
Identifies potential DNS cache poisoning vulnerabilities
Verifies CAA records for SSL/TLS certificate issuance control
Checks for open DNS resolvers (which can be abused for DDoS attacks)

Performance Analysis

Measures DNS response times from multiple locations
Evaluates TTL (Time To Live) settings for optimal caching
Checks for round-robin or geo-distributed DNS configurations
Identifies potential performance bottlenecks

Miscellaneous Checks

Verifies SOA (Start of Authority) record configuration
Checks for proper glue records if applicable
Identifies deprecated or unnecessary DNS records
Ensures proper wildcard DNS configuration if used

Common DNS Issues Detected

Our DNS Health Check tool can identify numerous common DNS issues, including:

Missing Redundancy

Having only one nameserver creates a single point of failure. Best practice is to have at least two nameservers on different networks.

Inconsistent Records

Different nameservers returning different answers for the same query, which can cause unpredictable behavior.

Lame Delegation

When a nameserver is listed as authoritative for a domain but doesn't actually respond authoritatively for that domain.

Missing or Invalid MX Records

Improper mail exchanger records can prevent email delivery to your domain.

Incorrect SPF Records

Malformed SPF records or records with syntax errors that can affect email deliverability.

DNSSEC Misconfiguration

Improperly configured DNSSEC can make your domain inaccessible to validating resolvers.

Excessive TTL Values

TTL values that are too high can slow down propagation of DNS changes, while values that are too low can increase DNS query load.

Missing Reverse DNS

Absence of PTR records for your IP addresses, which can affect email deliverability and server credibility.

Using Our DNS Health Check Tool

Our DNS Health Check tool makes it easy to evaluate your domain's DNS health:

Enter your domain name in the input field
Click the "Run Health Check" button
Wait while our tool performs a comprehensive analysis of your domain's DNS configuration
Review the detailed results, which include:
- An overall health score
- Critical issues that need immediate attention
- Warnings about potential problems
- Recommendations for improvements
- Detailed explanations of each finding

Tip: Run DNS health checks regularly, especially after making changes to your DNS configuration, to ensure everything is working correctly.

Interpreting DNS Health Check Results

Our DNS Health Check tool categorizes findings into three levels:

Critical Issues

Problems that require immediate attention as they may be causing service disruptions or exposing security vulnerabilities. Examples include missing nameservers, lame delegation, or conflicting records.

Warnings

Issues that aren't causing immediate problems but could lead to issues in the future or represent suboptimal configurations. Examples include missing email authentication records or suboptimal TTL values.

Recommendations

Suggestions for improving your DNS configuration beyond the basics. These aren't problems per se, but implementing them can enhance performance, security, or reliability. Examples include implementing DNSSEC or adding CAA records.

For each finding, our tool provides:

Description: What the issue is
Impact: How it affects your domain
Resolution Steps: How to fix the issue
Technical Details: Specific information about the finding

DNS Best Practices

Based on industry standards and our experience, here are some DNS best practices to follow:

Use Multiple Nameservers: Have at least 2-4 nameservers on different networks and geographic locations.
Implement DNSSEC: Add digital signatures to your DNS records to prevent tampering.
Set Appropriate TTL Values: Use TTLs of 3600-86400 seconds (1-24 hours) for stable records, and lower values (300-1800 seconds) when planning changes.
Configure Email Authentication: Implement SPF, DKIM, and DMARC records to prevent email spoofing.
Use CAA Records: Control which Certificate Authorities can issue SSL/TLS certificates for your domain.
Monitor DNS Health: Regularly check your DNS configuration for issues.
Keep Records Consistent: Ensure all nameservers return the same answers for your domain.
Remove Obsolete Records: Clean up old or unused DNS records to prevent confusion.
Document Your DNS Configuration: Maintain documentation of your DNS setup for reference.

Next Steps

After running a DNS Health Check, you might want to explore:

DNS Lookup Tool - Query specific DNS records for your domain
DNS Propagation - Check if your DNS changes have propagated
DNSSEC Validator - Verify your DNSSEC implementation
Email Authentication - Learn more about SPF, DKIM, and DMARC
DNS Security Best Practices - Comprehensive guide to securing your DNS