Audit SPF, DKIM and DMARC DNS for sheet domains with Google DNS, GPT-4o-mini and Telegram

Quick Overview

This workflow checks SPF, DKIM, DMARC, and MX DNS records for a list of domains using Google Public DNS over HTTPS, compares the results to the previous run, and sends a Telegram message only when problems appear, get fixed, or records change.

How it works

1. Runs daily at 8:00 or on-demand via a manual test trigger.
2. Reads a comma-separated list of domains (optionally with DKIM selectors) and builds DNS queries for MX, SPF (TXT), DMARC (TXT), and each DKIM selector (TXT).
3. Calls Google Public DNS over HTTPS (dns.google/resolve) to resolve each requested record, retrying failed requests and treating unresolved lookups as unknown rather than missing.
4. Evaluates each domain’s responses to flag issues such as missing/unsafe SPF, missing or weak DMARC settings, missing/revoked DKIM selectors, and missing MX.
5. Compares current results with stored results from the last scheduled run to generate a change-only report (new issues, fixed issues, and edited record values), while manual runs produce a full report.
6. Sends the compiled alert message to a Telegram chat.

Setup

1. Add your domains in the domain list field (comma-separated) and include any DKIM selectors after a colon, for example: example.com, mycompany.com:google|selector1.
2. Create a Telegram bot, add the Telegram credential in n8n, and set the target chat ID in the Telegram send message step.
3. Adjust the schedule time if needed, then run a manual test to verify the report before activating the workflow.