1. Isolation of Risk
- Separation of Identity: By using subdomains, businesses can keep their main domain separate from any potential vulnerabilities introduced by third-party providers. If the third-party provider is compromised, the risk is contained within the subdomain rather than impacting the main domain.
- Limiting Impact: If a subdomain is compromised, it won't affect the main domain's reputation and deliverability. This containment helps protect the overall brand from being associated with phishing or spam activities.
2. Control Over DNS Records
- Granular Control: Subdomains allow businesses to set specific DNS records (SPF, DKIM, DMARC) tailored to the third-party provider. This control reduces the risk of misconfigurations that could occur if all providers were authenticated on the main domain.
- Easier Management: Subdomains simplify the management of email authentication, as each third-party provider can have its own dedicated policies and settings without interfering with the main domain's email configuration.
3. Protection Against Spoofing
- Reducing Spoofing Risk: Allowing a third-party provider to authenticate using the main domain could enable them to send emails that appear as if they are directly from the business's main domain. This increases the risk of spoofing, where malicious actors could send fraudulent emails that seem legitimate to recipients.
- Enhanced Trust: By using a subdomain, businesses can clearly distinguish emails sent by third-party providers. This transparency helps maintain trust with recipients, as they can easily identify legitimate communications.
4. Compliance and Security
- Regulatory Compliance: Some industries have strict regulations around email authentication and data protection. Using subdomains helps businesses adhere to these regulations by clearly defining the boundaries between their internal communications and those managed by third parties.
- Security Posture: Maintaining a robust security posture is easier when third-party services are segregated to subdomains. It ensures that the primary domain remains protected by stricter security policies while still allowing third-party providers to operate within a controlled environment.
5. Brand Protection
- Preserving Brand Reputation: Any issues with a third-party provider's service, such as sending spam or phishing emails, will primarily impact the subdomain rather than the main brand. This strategy helps protect the main brand's reputation and credibility.
- Visibility and Tracking: Subdomains provide better visibility into the activity and behaviour of emails sent through third-party providers. It allows businesses to monitor and track the performance and security of each provider individually.