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How to Use the Lookup Tool

A guide on how to use the main lookup tool.

Deep DNS TeamOctober 23, 20256 min read

How to Use the Deep DNS Lookup Tool

The Deep DNS lookup tool provides instant access to comprehensive DNS information for any domain. Whether you're troubleshooting connectivity issues, verifying DNS configurations, or auditing domain security, our tool delivers detailed results in seconds with an intuitive, user-friendly interface.

Quick Start Guide

1. Access the Lookup Tool

To begin, simply navigate to the Deep DNS homepage.

  • Visit the Deep DNS homepage in your web browser.
  • The DNS lookup search bar is prominently displayed at the top of the page.
  • No account or registration required—you can start searching immediately.

2. Enter Your Query

Type the domain name you want to investigate into the search bar. Our tool supports various valid input formats:

example.com
www.example.com
subdomain.example.com
shop.example.co.uk

Important Notes:

  • Enter only the domain name (do not include http:// or https:// protocols).
  • Include subdomains if you are querying specific hosts (e.g., mail.example.com).
  • Ensure correct spelling—typos will query the wrong domain.
  • Internationalized Domain Names (IDN) are fully supported.

3. Initiate the Lookup

You can initiate the lookup in two ways:

  • Click the "Lookup" or "Search" button.
  • Press the Enter key on your keyboard.

What Happens Next:

The tool simultaneously queries multiple authoritative DNS servers and resolvers to retrieve a wealth of information, including:

  • All DNS record types (A, AAAA, MX, TXT, NS, SOA, etc.)
  • Record values and configurations
  • TTL (Time to Live) settings
  • Nameserver information

Most lookups complete within 1-3 seconds.

Understanding the Results Dashboard

Once the lookup completes, you'll see a structured breakdown of all DNS records associated with the queried domain. The results dashboard is organized into several key columns:

Record Type Column

This column shows the DNS record type (e.g., A, MX, TXT). Each record type serves a specific purpose:

  • A Record: Maps a domain name to an IPv4 address.
  • AAAA Record: Maps a domain name to an IPv6 address.
  • CNAME Record: Creates an alias from one domain name to another.
  • MX Record: Specifies mail servers responsible for receiving email messages.
  • TXT Record: Holds text information, often used for verification or email security (e.g., SPF, DKIM).
  • NS Record: Indicates the authoritative name servers for a domain.
  • SOA Record: Stores important information about the domain, such as the primary name server and the domain administrator's email.

For more detailed explanations, please refer to Understanding DNS Records.

Record Value Column

This column displays the actual data contained in each DNS record. The format varies by type:

A Record:      192.0.2.1
AAAA Record:   2001:0db8:85a3::8a2e:0370:7334
CNAME Record:  example.com
MX Record:     10 mail.example.com
TXT Record:    "v=spf1 include:_spf.google.com ~all"
NS Record:     ns1.example.com

TTL Column

This column shows the Time to Live (TTL) in seconds. The TTL indicates how long resolvers should cache this record before querying again:

  • Low TTL (300-900 seconds): Ideal for situations requiring frequent updates and faster propagation.
  • Medium TTL (3600-7200 seconds): A balanced approach for most domains.
  • High TTL (43200-86400 seconds): Suitable for stable configurations, reducing query load on DNS servers.

Learn more about this crucial setting in What is TTL?.

Advanced Features for In-Depth Analysis

Record Type Filtering

Our tool allows you to filter results by specific record categories, helping you focus on the information you need:

  • Core Records: A, AAAA, CNAME
  • Mail Records: MX, SPF/TXT
  • Infrastructure: NS, SOA
  • All Records: View the complete DNS configuration.

Multi-Resolver Comparison

Compare results across different DNS resolvers (e.g., Google DNS, Cloudflare, OpenDNS) to:

  • Verify global DNS propagation.
  • Identify resolver-specific caching issues.
  • Troubleshoot inconsistent DNS responses.

Historical Data

Some Deep DNS features include historical DNS data, enabling you to:

  • Monitor when DNS records were modified.
  • Compare current versus previous configurations.
  • Identify unauthorized changes.

Common Use Cases and Troubleshooting

Troubleshooting Website Connectivity

Scenario: Your website isn't loading.

Steps:

  1. Look up the domain's A or AAAA record.
  2. Verify the IP address points to the correct server.
  3. Check if the domain has any records at all.
  4. Compare results across different resolvers.

Common Issues:

  • No A/AAAA record: The domain is not configured to point to a server.
  • Wrong IP address: Indicates an outdated configuration.
  • Different results across resolvers: DNS propagation is likely still in progress.

Verifying DNS Configuration Changes

Scenario: You've recently updated DNS records.

Steps:

  1. Perform a lookup immediately after making changes.
  2. Note the current TTL value.
  3. Wait for the TTL duration to expire.
  4. Perform another lookup to verify propagation.
  5. Use the multi-resolver check for global verification.

Pro Tip: Lower the TTL before planned changes to speed up propagation, then raise it afterward for stability.

Investigating Email Delivery Issues

Scenario: Emails are not being received.

Steps:

  1. Look up MX records to verify mail server configuration.
  2. Check TXT records for SPF, DKIM, and DMARC.
  3. Verify MX priority values are correct.
  4. Ensure mail servers resolve to valid A/AAAA records.

Red Flags:

  • No MX records: Email delivery is impossible.
  • Invalid MX targets: Points to non-existent mail servers.
  • Missing SPF/DMARC: Indicates poor email authentication, leading to emails being marked as spam.

For comprehensive email security details, see Improving Email Security.

Security Auditing

Scenario: Reviewing your domain's security posture.

What to Check:

  • TXT Records: Verify SPF, DKIM, DMARC configurations.
  • CAA Records: Ensure Certificate Authority Authorization is set to restrict which CAs can issue certificates for your domain.
  • DNSSEC: Check for DNS Security Extensions implementation to protect against DNS spoofing.
  • Nameservers: Confirm that only authorized DNS providers are listed.

Tips for Effective Lookups

Best Practices

  • Be Specific with Subdomains:

    • ✅ Good: mail.example.com (for specific mail server configurations)
    • ❌ Vague: example.com (may miss subdomain-specific configurations)

  • Query After DNS Changes:

    • Wait for the old TTL to expire before expecting new results.
    • Check multiple resolvers to confirm global propagation.
    • Clear your local DNS cache if you are seeing stale results.

  • Use Correct Record Type: If you know what you're looking for, filter by specific record types for cleaner and more relevant results.

Interpreting Common Patterns

  • Multiple A Records:

    example.com.    A    192.0.2.1
example.com.    A    192.0.2.2
example.com.    A    192.0.2.3

    Indicates: Load balancing across multiple servers.

  • CNAME Chain:

    www.example.com.     CNAME    example.com.
example.com.         CNAME    hosting-provider.com.
hosting-provider.com. A       192.0.2.1

    Indicates: Multiple levels of aliasing, which can impact performance.

  • High-Priority and Low-Priority MX:

    example.com.    MX    10    mail1.example.com.
example.com.    MX    20    mail2.example.com.

    Indicates: A primary mail server (priority 10) with a backup/failover server (priority 20).

Next Steps

Power User Tip: Bookmark frequently checked domains for quick access, and set up automated monitoring for critical infrastructure domains to receive alerts when DNS configurations change unexpectedly.

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