Senior Network & Systems Administrator

Sr. Network and Systems Administrator

Pay Range: $115,000 - $145,000/year

Position Summary 

The Sr. Network and Systems Administrator is the senior technical owner of the organization's hybrid infrastructure, responsible for the design, performance, security, and reliability of its network, server, virtualization, identity, and Microsoft 365/Azure environments. This role serves as the final Tier 2 and Tier 3 escalation point, leads infrastructure projects from planning through completion, and drives long-term improvements through root cause analysis, automation, and documentation rather than repeated short-term fixes.

Working closely with Help Desk, the Security Administrator, and IT leadership, this position requires someone who can operate independently with minimal direction, make sound judgment calls on when to escalate, prioritize competing demands during outages and maintenance windows, and clearly explain technical issues and trade-offs to non-technical stakeholders.

Key Responsibilities

Network Administration

• Own the design, configuration, and maintenance of LAN, WAN, wireless, and VPN environments across multiple sites, including site-to-site and SSL/remote-access VPNs.
• Configure and manage Layer 2 and Layer 3 switches, routers, firewalls, and wireless infrastructure (e.g., Cisco, Aruba, SonicWall, Ubiquiti), including VLANs, subnetting, routing (OSPF, BGP), NAT, and Spanning Tree.
• Lead troubleshooting of complex and intermittent connectivity issues such as packet loss, routing problems, and VPN failures, using tools like Wireshark, tcpdump, traceroute, and pathping to isolate root cause.
• Plan and execute network changes and hardware replacements, including firewall cutovers, with minimal downtime and documented rollback plans.
• Maintain accurate network documentation, diagrams, IP schemas, and configuration standards.
• Manage relationships with ISPs, vendors, and service providers, including escalations and performance accountability.

Systems Administration

• Administer Windows Server environments and core server roles, including DNS, DHCP, file services, DFS, IIS, Certificate Services, and NPS.
• Manage hybrid identity across on-premises Active Directory and Microsoft Entra ID, including domain controllers, FSMO roles, replication health, Group Policy design and troubleshooting, and security/distribution/Microsoft 365 group structure.
• Administer VMware and/or Hyper-V virtualization platforms, including host management, storage provisioning, snapshot practices, and VM performance troubleshooting.
• Own the patching and maintenance lifecycle for servers and infrastructure, following change management practices and scheduled maintenance windows.
• Design, manage, and regularly test backup and disaster recovery solutions, including offsite and immutable backups, defined recovery objectives (RPO/RTO), documented recovery runbooks, and routine restore validation.
• Diagnose performance issues across network, server, and application layers to determine where a problem truly originates.

Cloud & Infrastructure

• Administer Microsoft 365 services, including Exchange Online, Teams, SharePoint, and licensing.
• Manage endpoint and access services through Intune, Autopilot, MFA, and Conditional Access policies, and investigate sign-in failures, lockouts, and suspicious login activity using Entra ID logs.
• Administer Azure resources and lead or support cloud migration projects, such as moving workloads, file services, or email from on-premises to the cloud.
• Monitor system performance and capacity, and plan for future growth.
• Develop PowerShell scripts and automation (including scheduled tasks and Azure Automation) for recurring tasks such as user provisioning and offboarding, reporting, and environment cleanup.

Security

• Partner with the Security Administrator on compliance, security initiatives, and security control implementation.
• Apply the principle of least privilege and defense-in-depth practices across the environment, including securing administrative accounts through separate admin identities and PAM/PIM.
• Lead vulnerability remediation and system hardening efforts on network and server infrastructure.
• Participate in incident response, including containment of compromised systems or ransomware, log review, and post-incident recovery.
• Support endpoint security tools and verify that security controls and backups function as intended.

Support & Project Work

• Serve as the senior Tier 2 and Tier 3 escalation point for Help Desk, and mentor and share knowledge with junior IT staff.
• Prioritize and triage competing demands, such as outages, maintenance windows, and escalations, based on business impact, and keep stakeholders informed throughout.
• Lead infrastructure and technology projects end to end, from scoping and planning through pilot, cutover, and handoff.
• Investigate recurring issues to identify and permanently resolve root causes, adding monitoring and documentation to prevent recurrence.
• Communicate technical issues, risks, and recommendations to IT leadership and non-technical stakeholders in clear, business-focused terms.
• Develop and maintain technical documentation, runbooks, and standards, and identify opportunities for process improvement and automation.

This job description outlines the general nature and level of work expected for this role. It is not intended to be an exhaustive list of all duties, responsibilities, or qualifications. The company reserves the right to modify job duties at any time based on business needs.

Qualifications

Required

• Bachelor's degree in Information Technology, Computer Science, or related field, or equivalent experience.
• 5+ years of hands-on network and systems administration experience in a multi-site, hybrid (on-premises and cloud) environment, including leading infrastructure projects from start to finish.
• Advanced experience with Windows Server, Active Directory, Group Policy, DNS, and DHCP, including hybrid identity with Microsoft Entra ID.
• Hands-on experience administering Microsoft 365, including Exchange Online, Intune, MFA, and Conditional Access.
• Strong working knowledge of networking technologies, including switching, routing, VLANs, subnetting, firewalls, and site-to-site VPNs.
• Experience administering VMware or Hyper-V virtualization platforms and related storage.
• Experience designing, maintaining, and testing backup and disaster recovery solutions.
• Proven, methodical troubleshooting skills with a track record of identifying and resolving root causes rather than applying repeated workarounds.
• Ability to work independently with minimal direction, exercise sound judgment on when to escalate, and manage multiple priorities during high-pressure situations.
• Excellent communication skills, including the ability to explain technical concepts to non-technical stakeholders and IT leadership.
• Strong documentation, organizational, and collaboration skills.

Preferred

• Experience administering Azure cloud services and leading cloud migration projects.
• Proficiency in PowerShell scripting and automation.
• Security and compliance experience, including PAM/PIM, endpoint security, and incident response.
• Experience with routing protocols such as OSPF and BGP.
• Experience with Cisco, Aruba, SonicWall, or Ubiquiti network equipment.
• Industry certifications such as CCNA or CCNP, Microsoft Certified: Azure Administrator Associate or Microsoft 365 Administrator, VMware VCP, Network+, or Security+.

Job Details

Job Title: Sr. Network and Systems Administrator

Department: LINX Corporate

Reports To: IT Director

FLSA Status: Exempt

Visa Sponsorship: LINX does not offer visa sponsorship for this position. Candidates must be legally authorized to work in the United States without current or future sponsorship.

Benefits

• 401(k) with 50% employer match up to first 5%
• Insurance options including Medical plans with Flexible Spending and/or Health Savings Accounts, Disability, Dental and Vision
• 8 Paid Holidays
• 3 weeks Paid Time Off (PTO) combining sick pay and vacation days
• Career growth opportunities

Posting Deadline

This position will remain open until December 31, 2026 or until filled.

Equal Employment Opportunity Statement

We are an Equal Opportunity Employer and value diversity in the workplace. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex, sexual orientation, gender identity, national origin, disability, veteran status, or any other protected characteristic.

Colorado Pay Transparency Statement

In compliance with the Colorado Equal Pay for Equal Work Act, the salary range for this role is listed above. Actual compensation within the range will be determined based on factors such as experience, skills, internal equity, and geographic location.