Proofpoint Sues Facebook Over Use Of Lookalike Domains ‘By using domain names similar to those of well-known companies, Proofpoint is able to execute a more effective [security awareness] training program,’ Proofpoint writes in a complaint filed against Facebook. By Michael Novinson February 11, 2021, 04:53 PM EST Proofpoint has sued Facebook seeking permission to keep using domain names that look like Facebook and Instagram as part of its security awareness training exercises. The Sunnyvale, Calif.-based email security vendor was hit Jan. 25 with a decision from an arbitrator ordering the transfer of five lookalike domain names from Proofpoint to Facebook within ten business days. The decision came in response to a complaint Facebook filed Nov. 30 with an administrative body, where the social media giant alleged that Proofpoint registered and used the domain names in bad faith.