Linux System Administrator jobs in United States

• Network Administration: Manage and maintain the stacked access switches (Layer 2) and core L3 switches. Configure and troubleshoot VLANs, DHCP relay, inter-VLAN routing, and Port-Channels (LAGs). Administer FortiGate firewalls, including NAT policies, security rules, SD-WAN settings, and DNS filtering. Ensure redundancy and routing between dual internet connections (ADSL), segregating VLAN traffic by route. Maintain and monitor the MPLS WAN link and ensure routing for internal applications is correctly prioritized. Monitor network health, throughput, and uptime using SNMP and preferred monitoring tools. Setup and manage site-site VPN connections. Implement network and system monitoring tools.

• System Administration: Manage the Windows Server 2025 infrastructure including Active Directory (user / group management, GPO). DHCP & DNS configuration, cleanup, and failover planning. Maintain local DNS resolution hierarchy with proper upstream forwarders. Support future DHCP failover / high-availability setup with a secondary server. Perform system patching, user provisioning, and asset lifecycle management. Troubleshoot and support endpoint connectivity (IP issues, DNS resolution, etc.).

• Security & Compliance: Implement and monitor network security policies (ACLs, port security, VLAN isolation). Ensure firewall rules align with security best practices for voice, data, and web traffic. Regularly audit logs, firmware updates, and access control configurations.

• Support & Operations: Provide Tier-2 / Tier-3 technical support for network and server incidents. Maintain documentation for all configurations, network topology, and incident history. Collaborate with vendors, ISPs, and internal stakeholders for upgrades or escalations. Plan and roll-out maintenance changes. Prepare RCA for any incidents. Prepare Change Management for any production changes.

• CCNP (Enterprise or Security) – must be current
• MCSE (Windows Server) – must be current or recently renewed
• 5+ years of hands-on experience in network & system administration
• Deep understanding of
• Layer 2 / 3 switching, spanning tree, port channels
• DHCP / DNS setup in enterprise networks, Routing protocols (OSPF, static routes, etc)
• FortiGate firewall configuration
• Stacked switches (Huawei, Cisco, Aruba, or equivalent)
• Managing VLAN-heavy environments
• MPLS & WAN routing policies

• Experience in contact center environments
• Scripting or automation (PowerShell, Python, etc.)
• Familiarity with IP telephony QoS and VoIP-aware routing
• Experience using network monitoring tools (PRTG, SolarWinds, etc.)
• Understanding of SD-WAN features and policy-based routing

• Strong analytical and troubleshooting mindset
• Clear communicator, especially under pressure
• Capable of writing documentation and knowledge base articles
• Comfortable working independently and with cross-functional teams

Candidates must hold current CCNP and MCSE certifications and have over 5 years of hands-on experience in network and system administration.

A deep understanding of network protocols, firewall configuration, and enterprise network management is essential.