Case Study: Tessella achieves 100% DMARC compliance and stronger email security with Red Sift OnDMARC

Tessella maximize email security with 100% DMARC compliance

Tessella (now part of Capgemini Engineering) needed to strengthen email security and improve DMARC compliance across its domains. Working with **Red Sift** and its **OnDMARC** product, the team aimed to move from an outdated “p=none” posture to a verified, enforceable DMARC setup that would confirm legitimate mail and stop spoofing attempts.

Using **Red Sift OnDMARC**, Tessella quickly implemented DMARC across 24 domains, automated SPF updates, and gained ongoing visibility into sending sources. The results were strong: email deliverability reached 99.5%, more than 2,000 monthly spoofs from over 200 senders were blocked, and 97% of 126 sending sources were found to be fraudulent in 90 days and safely stopped.

Tessella

Steve Jackson

Head of Information Systems