Microsoft Exchange Administrator

Leidos is seeking a Senior Exchange Administrator to lead the design, operation, and optimization of our Microsoft Exchange and O365 messaging environments that support mission-critical government and commercial customers. In this role, you will architect and maintain secure, highly available mail systems; manage mail flow, compliance, and retention; and resolve complex issues as a Tier III expert. You will collaborate closely with cybersecurity, network, and systems engineering teams in a mission-driven, highly collaborative culture that values integrity, innovation, diversity, and continuous learning. Leidos offers competitive pay, robust benefits, flexible work options, and opportunities to work on impactful, real-world projects in national security, health, and engineering., * Design, configure, and maintain Microsoft Exchange and O365 messaging environments

• Manage mail flow, connectivity, security, and high availability for mission-critical systems
• Perform upgrades, patching, backup, and recovery of Exchange infrastructure
• Implement and monitor security, compliance, and retention policies
• Troubleshoot complex messaging issues and provide Tier III support
• Automate routine administration with Power
• Shell and related tools
• Collaborate with cybersecurity, network, and systems teams on integrated solutions
• Document architecture, standards, and procedures and mentor junior staff

• Microsoft Exchange Server administration
• Microsoft 365 / Exchange Online
• Power
• Shell scripting
• Mail flow and transport rules
• Security, compliance, and retention policies
• Hybrid Exchange configurations
• Backup and disaster recovery for messaging systems
• Identity and access management (AD/Azure AD)
• Performance monitoring and troubleshooting
• Network and email security standards (TLS, SPF, DKIM, DMARC)