Can reputation contamination spread through shared DNS?

Shared DNS configurations can create contamination pathways:

SPF record sharing where multiple domains include the same third-party IP ranges. If one domain abuses those IPs, providers may scrutinize all domains using them.

DKIM key sharing across domains means a compromised key affects all domains using it.

Organizational inference where providers detect domains sharing DNS infrastructure and may associate their reputations.

Authentication failures from misconfigured shared records propagate across all affected domains.

Domains requiring strong isolation should maintain completely independent DNS configurations, including separate DKIM keys and distinct SPF records.

Shared DNS is like ships using the same registration documents. If one captain's papers are revoked, port authorities may question all vessels bearing similar documentation.