ESDAR-Checker (Email Security DNS Advanced Records Checker)

Version 2.0.0

A Python tool to check email security DNS records (DMARC, SPF, DKIM, MX) for one or multiple domains.

Features

• Check DMARC records
• Check SPF records
• Check DKIM records (with support for multiple selectors)
• Check MX records
• Process single domain or multiple domains from file
• Export results to CSV
• Robust error handling (continues processing on errors)
• Support for multiple DKIM selectors per domain
• Improved CSV handling (proper formatting)

Prerequisites

• Python 3.7 or higher
• PowerShell (for Windows) or terminal access
• you have to be able to run Scripts via Powershell or at least to run the following command in Powershell: Set-ExecutionPolicy Unrestricted -Scope Process (Stackoverflow)

Installation

1. Clone the repository to your local machine
2. Navigate to the ESDAR-Checker directory
3. Create a virtual environment:

   python -m venv .venv

4. Activate the virtual environment:

   # Windows PowerShell
   .\.venv\Scripts\activate
   
   # Linux/Mac
   source .venv/bin/activate

5. Install dependencies:

   pip install -r requirements.txt

6. (Optional) Configure output path in config.py or use --output_path parameter

Usage

Check a single domain

python esdar-checker_v2.py --domain "google.com"

Check a single domain with DKIM selector

python esdar-checker_v2.py --domain "google.com" --selector "google"

Check a single domain with multiple DKIM selectors

python esdar-checker_v2.py --domain "google.com" --selectors "default,google,selector1"

Check multiple domains from file

python esdar-checker_v2.py --domains_file "resources/input/input_urls.csv"

Append results to existing CSV file

python esdar-checker_v2.py --domain "google.com" --append yes

Specify custom output path

python esdar-checker_v2.py --domain "google.com" --output_path "C:/Users/YourName/Downloads/results/"

Continue processing on errors

python esdar-checker_v2.py --domains_file "domains.txt" --skip_errors

Custom DNS timeout

python esdar-checker_v2.py --domain "google.com" --timeout 15

Command-Line Arguments

Required (one of):

• --domain DOMAIN: Check a single domain
• --domains_file PATH: File containing domains (one per line or CSV)

Optional:

• --selector SELECTOR: Single DKIM selector to check
• --selectors "SELECTOR1,SELECTOR2": Multiple DKIM selectors (comma-separated)
• --append yes/no: Append to existing CSV file (default: no)
• --output_path PATH: Custom output directory path
• --timeout SECONDS: DNS query timeout in seconds (default: 10)
• --skip_errors: Continue processing other domains if one fails

Input File Format

The input file can be:

• Plain text: One domain per line
• CSV: First column should contain domain names (header row is automatically skipped)

Example plain text file:

google.com
microsoft.com
github.com

Example CSV file:

Domain
google.com
microsoft.com
github.com

Output

Results are saved to esdar-check_result.csv in the output directory (default: resources/output/).

CSV columns:

• Domain: The checked domain
• MX Record: MX records (priority and mail server)
• SPF Record: SPF record if found
• DKIM Record: DKIM record(s) for the provided selector(s)
• DMARC Record: DMARC record if found

Configuration

Edit config.py to:

• Set default output path (RELATIVE_FILE_PATH)
• Configure nameservers for DNS lookups (NAMESERVER_LIST)

Troubleshooting

"File is open in another program"

Close the CSV file in Excel or another program before running the script.

"No DNS records found"

• Check if the domain exists
• Verify DNS connectivity
• Some domains may not have all security records configured

"DNS query timeout"

• Increase timeout with --timeout parameter
• Check your internet connection
• Try different nameservers in config.py

Known Issues (Fixed in v2.0.0)

- CSV formatting issues - **FIXED**
- Multiple selectors support - **ADDED**
- Error handling improvements - **FIXED**
- DMARC/DKIM lookup issues - **FIXED**

Use Case

This script helps users check any number of domains or URLs for the following email security DNS records:

• DMARC (Domain-based Message Authentication, Reporting & Conformance)
• SPF (Sender Policy Framework)
• DKIM (DomainKeys Identified Mail)
• MX Records (Mail Exchange)

The script checks if DNS TXT records exist for the above points and stores them for further use. Results can be displayed in the terminal or written to a CSV file.

License

See LICENSE file for details.

Author

Merlin von der Weide Version 2.0.0 - 2025