Sr. Systems Administrator - Office 365 / Exchange

Neumo Holdings LLC; Fairfield (CA); On-site; USD 120,000 - 140,000; Full time

Job summary

Neumo Holdings LLC in Fairfield, CA, seeks a Sr. Systems Administrator for Office 365 / Exchange to manage Exchange on-premises and Exchange Online, plus 365 tenant administration and security.

The role focuses on hybrid environments, Proofpoint, eDiscovery, PRA, and compliance, with a leadership stance within the SysAdmin team. A CLETS background check is required to work in the United States.

Qualifications

• 6+ years of experience in enterprise messaging administration.
• Experience with hybrid Exchange design and troubleshooting.
• Experience with Proofpoint, eDiscovery, PRA, and compliance.
• MCSE Messaging / M365 Messaging Administrator certifications preferred.
• Strong PowerShell automation skills.
• Ability to work across sites and datacenters.

Responsibilities

• Lead administration of Exchange on-premises including DAG configuration, mailbox databases, connectors, transport rules, and hybrid mail flow.
• Oversee Exchange Online and Microsoft 365 messaging services, ensuring performance and compliance.
• Manage hybrid environments including Entra Connect, identity sync, and coexistence strategies.
• Maintain and optimize Proofpoint (email security, DLP, TAP, encryption, routing).
• Support Teams/Outlook integration, shared mailboxes, and mail routing.
• Troubleshoot advanced messaging issues across hybrid environments.

Skills

Microsoft Exchange

Exchange Online

Microsoft 365

PowerShell

eDiscovery

Proofpoint

Hybrid architecture

DNS/PKI

Mail flow

Documentation

Communication

Education

MCSE Messaging

M365 Messaging Administrator

Security Administrator

Tools

Entra Connect

DAG

Exchange Admin Center

Job description

If you are unable to complete this application due to a disability, contact this employer to ask for an accommodation or an alternative application process.

Sr. Systems Administrator - Office 365 / Exchange

IT Managed Services Full Time Fairfield, CA, US

2 days ago Requisition ID: 2838

Salary Range: $120,000.00 To $140,000.00 Annually

Job Summary:

This senior-level technical position requires deep, hands‑on expertise with Microsoft Exchange (both on‑premises and Exchange Online), Microsoft 365 tenant administration, and enterprise messaging security platforms. The ideal candidate will have extensive experience designing, administering, and supporting hybrid Exchange environments, Proofpoint, eDiscovery, PRA, and compliance frameworks.

This role serves as a technical leader within the SysAdmin team and is responsible for ensuring secure, reliable, high‑performance communication systems across the organization. The environment spans multiple sites, datacenters, and a hybrid cloud infrastructure.

This position requires passing a CLETS background check and eligibility to work in the United States.

Duties and Responsibilities:

• Lead administration of Microsoft Exchange on‑premises including DAG configuration, mailbox databases, connectors, transport rules, and hybrid mail flow.
• Oversee Exchange Online and Microsoft 365 messaging services, ensuring performance and compliance.
• Manage hybrid environments including Entra Connect, identity sync, and coexistence strategies.
• Maintain and optimize Proofpoint (email security, DLP, TAP, encryption, routing).
• Support Teams/Outlook integration, shared mailboxes, and mail routing.

Security, Compliance, and Governance:

• Manage eDiscovery, PRA, retention, legal holds, and compliance requirements.
• Administer Exchange/M365 auditing, message tracing, and forensic analysis.
• Implement and maintain DKIM, DMARC, SPF, MFA, conditional access, and secure mail flow.

Operational & Project Leadership:

• Troubleshoot advanced messaging issues across hybrid environments.
• Lead upgrades, migrations, and modernization efforts.
• Coordinate cross‑team initiatives involving security, networking, and identity.

Documentation & Process Improvement:

• Maintain detailed system documentation, diagrams, and SOPs.
• Improve operational workflows and knowledge base content.

Education and Experience:

• 6+ years of experience in enterprise messaging administration or equivalent.
• Preferred certifications: MCSE Messaging, M365 Messaging Administrator, Security Administrator.

Knowledge, Skills, and Abilities:

• Expert proficiency in Microsoft Exchange (on‑prem and cloud).
• Deep knowledge of Exchange hybrid architecture and troubleshooting.
• Strong proficiency with Microsoft 365 services including Teams, SharePoint, and Power Platform.
• Expertise with Proofpoint administration and mail hygiene solutions.
• Strong PowerShell automation skills for Exchange and M365.
• Understanding of PKI, SMTP, DNS, certificates, and encryption.
• Excellent communication and documentation skills.

Typical office environment with moderate noise levels.

Physical Demands:

Ability to remain in a stationary position for prolonged periods.

Frequent computer use and communication with staff and leadership.