IT Manager/Senior Systems Administrator

3Core Systems, Inc is an SAP and SuccessFactors Partner with employees located across the United States. Our organization is dedicated to customer and employee satisfaction. We provide High Quality, cost-efficient, and Competitive Solutions and Resources.

3Core Systems is looking for an IT Manager/Senior Systems Administrator for one of our clients in NYC or CT | Onsite 5 Days/Week

"US and those authorized to work in the US are encouraged to apply. We are unable to sponsor visas at this time"

Role: IT Manager/Senior Systems Administrator
Location: NYC or CT | Onsite 5 Days/Week
Duration: Full-time

Core responsibilities

• Identity and access governance: Lead the administration of Active Directory architecture, group design, and the service-account estate: service principal names, Entra ID application registrations, Graph API access, and credential rotation through our password vault. Maintain existing access standards, run periodic access and service-account reviews, and evaluate and process access exceptions in accordance with established approval procedures.
• File and storage services: administer the Windows and Samba file-server estate across headquarters, the offsite data center, and remote offices; manage capacity, quotas, and monitoring; plan and execute server and share migrations; oversee archiving, backup, and data-governance tooling.
• Email and collaboration platforms: administer Microsoft 365 and Exchange Online, including mail routing, mail security and filtering, DLP, retention and journaling, and the Teams, SharePoint, and OneDrive estate.
• Server and virtualization infrastructure: build, patch, and maintain the Windows Server estate on VMware vSphere; hands-on work with physical server hardware including racking, cabling, diagnostics, and component replacement.
• Network and perimeter: Administer and troubleshoot TCP/IP, DNS, DHCP, VLANs, wireless networks, certificates, and infrastructure-monitoring platforms. Configure, monitor, and manage firewalls to enforce access controls and protect the corporate network against unauthorized access and cyber threats. Manage telecom and ISP vendor relationships.
• Security operations: administer endpoint protection, data-governance, and email-security platforms; manage multi-factor authentication, conditional access, and geographic access restrictions; run the security-awareness and phishing-simulation program; respond to alerts and vulnerabilities.
• eDiscovery and legal hold: perform mailbox and file searches in support of subpoenas, regulatory requests, and litigation; preserve, collect, and produce data under the direction of counsel and Compliance, handling all of it with strict confidentiality.
• Telephony and voice services: support the current Avaya PBX, associated analog lines, and voice-service vendors; troubleshoot and coordinate resolution of telephony incidents, provisioning, and office moves. Assist with the planned transition of PBX operations to an outsourced provider and oversee the vendor relationship thereafter.
• Automation: use PowerShell and Python to automate provisioning, reporting, and task scheduling, and maintain our enterprise job scheduling platform.
• License, subscription, and vendor governance: Oversee software and cloud-service entitlements, licensing, renewals, procurement, and vendor relationships. Review user licensing and assignments across platforms such as Adobe, Box, Microsoft 365/Intune, Visual Studio, Verizon, Bloomberg, and similar services. Recommend and implement subscription changes that appropriately align user access, device management, security, operational needs, and vendor-licensing requirements.
• Project and vendor coordination: Own the technical delivery of internal and vendor-led infrastructure and security projects from requirements gathering, scoping, resource planning, testing, and implementation through acceptance and documentation. Define and maintain project plans, timelines, dependencies, risks, action items, and internal and vendor resource needs; track progress, escalate issues, and coordinate stakeholders through completion.
• Change management and IT control reviews: Maintain accurate records of material infrastructure, configuration, and access changes across on-premises systems, AWS, and managed-service-provider environments. Perform monthly reviews of Active Directory group membership, workstation configuration, local administrator access, server assignments, and system usage and monitoring; investigate and remediate discrepancies; and document findings, approvals, exceptions, and follow-up actions.
• IT security oversight and policy compliance: Maintain operational controls that support IT policies, client and regulatory due-diligence questionnaires (DDQs), and external security representations. Ensure documented policies, DDQ responses, and day-to-day practices remain aligned. Monitor and validate controls for password and credential rotation, service accounts, least-privilege access, patching and reboot compliance, and the documentation, approval, and periodic review of exceptions.
• Technical leadership and escalation: Route and prioritize support tickets, help coordinate support coverage and issue resolution, and serve as the technical escalation point for IT support staff. Mentor junior team members and promote clear documentation, consistent operational practices, and timely risk escalation.
• Facilities and critical-environment infrastructure: monitor and coordinate the power, cooling, and environmental systems supporting office technology rooms and server rooms, including UPS units, PDUs, circuits, temperature/humidity monitoring, and HVAC. Coordinate with building management, datacenter providers, electricians, and HVAC vendors during incidents, maintenance, capacity changes, and planned shutdowns.

Skills and qualifications

• In-depth knowledge of Microsoft Windows Server, Active Directory, Microsoft 365, MS Teams, and Multi-Factor Authentication.
• Hands-on experience administering non-human identity: service accounts, service principal names, Entra ID app registrations, and credential lifecycle management.
• Experience with VMware vSphere virtualization.
• Strong experience administering Windows file servers and network storage at scale - permissions, quotas, capacity monitoring, and migrations.
• Strong understanding of email flow and mail security, including routing, spam, malware, and DLP; hands-on experience with a secure email gateway (Proofpoint, Mimecast, or similar).
• Strong understanding of networking concepts and protocols (TCP/IP, DNS, DHCP, VLANs, etc.), coupled with experience in configuring, monitoring, and managing firewalls to secure the corporate network and enforce access controls.
• Experience with endpoint protection and data-governance platforms (CrowdStrike, Varonis, or similar).
• Proficiency with PowerShell for infrastructure automation, reporting, and administration.
• Hands-on experience with physical server hardware, including racking, structured cabling, hardware diagnostics, and component replacement (disks, memory, power supplies, etc.).
• Working knowledge of the power and environmental requirements of server rooms and network closets, including UPS systems, rack PDUs, electrical capacity, cooling, temperature/humidity monitoring, and escalation to facilities, data center, and building vendors.
• Proven experience as a Systems Administrator or similar role, with 7+ years managing enterprise IT infrastructure in a hands-on environment.
• Experience supporting DR, backup/restore testing, infrastructure monitoring, change control, and documented operational procedures.
• Experience operating and evidencing IT controls in a regulated or audited environment, including access reviews, change management, exception management, and policy compliance.
• Demonstrated experience with software and cloud-license governance, entitlement reviews, vendor renewals, and cost-conscious subscription management.
• Proven ability to lead technical projects and coordinate internal stakeholders, managed service providers, and other vendors from scope through implementation.
• Strong organizational skills, with the judgment to identify control gaps, document risks, drive remediation, and communicate status clearly to technical and non-technical stakeholders.

Preferred qualifications

• Bachelor's degree in Computer Science, Information Technology, or related field (or equivalent experience).
• Experience in financial services or another regulated, audited environment.
• Exposure to eDiscovery, legal hold, or regulatory production processes.
• Experience with cloud computing platforms such as AWS or Azure is a plus.
• Experience with configuration management tooling (Ansible, PowerShell DSC, or similar) is beneficial.
• Familiarity with market data platforms, particularly Bloomberg administration and entitlements.
• Familiarity with Avaya PBX administration, analog/POTS lines, and telecom vendor coordination.

What we re looking for

• Excellent problem-solving skills and attention to detail.
• Strong communication and interpersonal skills, including the ability to explain technical issues to non-technical stakeholders.
• Discretion and sound judgment when handling confidential company, employee, and legal data.
• A practical, service-oriented approach; able to balance competing priorities, document work clearly, and escalate risks appropriately.
• Comfortable serving as a technical escalation point and mentoring junior IT staff.

Working arrangements

• On-site only this is not a remote or hybrid role.
• Occasional scheduled after-hours work for patching windows and recovery testing.
• Ability to move and install IT equipment and work in server rooms, wiring closets, and office locations as needed.
• If located in NYC, must have the ability to travel to CT or our DR site in Westchester as needed.

Regards,

Recruiting Team

3Core Systems Inc

9101 Burnet Road, Suite 207, Austin, TX 78758