Sr. Systems Engineer

Join a high-impact infrastructure team supporting the migration of enterprise email security services from on-premises appliances to a cloud-based Proofpoint solution. This role offers the opportunity to help ensure a smooth transition with minimal disruption while working in an onsite environment in the greater DC metro area. Responsibilities

• Lead the migration from on-premises IronPort email security appliances to a cloud-based Proofpoint email security platform.
• Design, configure, and maintain Proofpoint as an enterprise service.
• Manage Proofpoint firewall rules and maintain block lists.
• Respond to requests to quarantine or release email messages.
• Support messaging security operations with a strong understanding of mail transport architecture and security gateways.
• Work with Linux servers and VMware environments as part of ongoing platform support.
• Collaborate with stakeholders to support a seamless transition and uninterrupted email services.

• Expert-level experience designing, configuring, and maintaining Proofpoint in an enterprise environment.
• Strong knowledge of email security operations, including firewall rules, block lists, and message quarantine/release processes.
• Deep understanding of MTA and Proofpoint Messaging Security Gateway, including version 8.x.
• Hands-on experience with Linux Server administration.
• Experience supporting VMware-based environments.
• Ability to work onsite and reside within a 50-mile driving radius of the Board offices in the greater DC metro area.
• U.S. citizenship is required.

Preferred Skills

• Experience supporting email security platform migrations in enterprise settings.
• Familiarity with working through background check and drug screen processes upon offer.
• Strong communication and collaboration skills for working with technical and business stakeholders.
• Ability to manage priorities in a fast-moving environment where candidates are reviewed as submitted.

Horizontal is committed to fostering a diverse, equitable, and inclusive workplace where everyone feels respected, supported, and empowered to contribute. We welcome applicants from all backgrounds and experiences who are excited to help deliver secure, reliable technology services.