DomainKeys Identified Mail uses a private key to sign email and a public key published through DNS to verify the signature. This allows a receiving server to check the signature and detect changes to the signed content, as Cloudflare’s DKIM guide explains. Source: Cloudflare: DKIM records

Check each sending service

Ask the email provider which services sign messages for the domain and which records each requires. Include marketing and operational messages in the review. This helps ensure the check covers the systems the business actually uses to contact travellers.

Verify the message that arrives

Send an agreed test from each relevant service and ask the provider to inspect its authentication results. Keep the test outcome with the configuration record. This gives the team evidence of the working message path after a setup or supplier change.

Written and updated by Travelgenix. Sources checked on 19 October 2026. Practical advice and examples are Travelgenix editorial guidance.