GAS Library Guide: Identifying Web Services via DNS Record Analysis

1. Purpose of Implementation

The goal of this script is to analyze DNS records (MX, TXT, CNAME, etc.) associated with a domain to "uncover" the underlying infrastructure and third-party tools.

• Identify Tech Stacks: Instantly determine if a site uses Google Workspace, Microsoft 365, or specific hosting providers.
• Verify DNS Configurations: Quickly check if security settings like SPF and DMARC are correctly implemented.
• Increase Efficiency: Eliminate the need to manually run dig commands or use web-based DNS checkers one by one.

2. Key Use Cases

• Sales & Pre-sales Research: Understand which email marketing or Marketing Automation (MA) tools (e.g., HubSpot, Marketo) a prospect uses to create tailored proposal materials.
• Security Audits: Identify missing SPF or DMARC records on a client's domain to propose security improvements.
• Infrastructure Migration Surveys: List current record settings in a spreadsheet when planning to migrate web sites or email servers.

3. How to Use the Library (Implementation Steps)

Step 1: Add the Library

1. Open your Google Sheet and go to Extensions > Apps Script.
2. Click the "Libraries +" icon on the left menu.
3. Enter the Script ID for the DNS Checker and click "Look up."
4. Set the Identifier to DNSChecker and add it.

Step 2: Write the Execution Code

Paste the following code into your Code.gs file. This will create a custom menu in your spreadsheet.

/**
 * Add custom menu when the spreadsheet opens
 */
function onOpen() {
  DNSChecker.addMenu(); 
}

/**
 * Check all domains in Column A (Detailed Mode)
 */
function checkAllDomains() {
  DNSChecker.checkSheet({ detailed: true });
}

Step 3: Run the Script

1. Enter domains (e.g., example.com) or URLs in Column A of your sheet.
2. Select "Simple Check" or "Detailed Check" from the newly added custom menu.
3. The service names and DNS records will automatically populate in Column B and beyond.

Note: You can also use the custom formula =DETECTSERVICES(A1) directly in a cell.

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