Freelance Core Network Engineer Jobs in Chicago, IL

Company Description EnterpriseLabs is a specialized services and consulting firm focused on helping organizations drive innovation and digital transformation. Team members collaborate closely with industry-leading organizations to build scalable, intelligent systems that deliver measurable impact. The environment emphasizes continuous learning, experimentation, and practical application of advanced technologies.

Role Overview 

We are seeking an experienced Network Engineer to support a broad network infrastructure modernization program spanning upgrades, migrations, operational improvements, and documentation.

The role will partner closely with Network Engineering, Security, IT, Facilities, Workplace, Builds, and Infrastructure teams to assess and modernize existing network environments, with a focus on improving reliability, manageability, and operational readiness.

The engineer will work across both hands-on implementation and infrastructure assessment, including switching and firewall upgrades, network re-IP initiatives, core network services, rack and cabling improvements, infrastructure inventory, monitoring integration, and technical documentation.

This is a highly execution-focused role for someone who can independently assess existing environments, identify technical and operational gaps, coordinate across internal teams and external vendors, and drive infrastructure initiatives through successful completion.

Work Details 

● Work model: Onsite Preferred/ Minimum 3 days 

● Primary location: San Francisco 

● Expected travel: up to 40% 

● Migration support: Some planned evening or weekend work may be required during network migration and maintenance windows 

Key Responsibilities 

Network Infrastructure Support 

● Support upgrades and lifecycle improvements across switching and firewall infrastructure.

● Assist with network re-IP, migration, and consolidation activities. 

● Prepare network infrastructure for planned migrations and maintenance windows.

 ● Validate network connectivity, routing, segmentation, and application reachability during and after changes. 

● Troubleshoot routing, switching, firewall, and general connectivity issues. 

● Assist with VLAN, subnet, gateway, routing, and firewall policy changes. 

● Verify that changes meet established network and security standards.

● Document implementation plans, validation steps, issues, and outcomes. 

● Coordinate implementation activities with internal engineering teams and external vendors. 

● Participate in migration windows and support post-change troubleshooting as required.

Network Services Support 

Assist with the configuration, migration, troubleshooting, and validation of core network services, including: 

● DHCP scopes, reservations, relay configuration, and lease validation.

● DNS records, forwarding, resolution, and service validation. 

● IP address management and network allocation tracking. 

● VLAN, subnet, and gateway documentation. 

● Monitoring and alerting for network infrastructure and supporting services. 

The engineer will validate that these services continue to operate correctly throughout infrastructure upgrades and network migrations. 

Infrastructure Assessment and Inventory 

● Perform a comprehensive stock take of existing network infrastructure. 

● Document installed switches, firewalls, access points, UPS systems, PDUs, optics, cabling, and related infrastructure. 

● Record device models, serial numbers, software versions, support status, rack locations, power connections, and network connectivity. 

● Review rack utilization, cabling conditions, power distribution, and equipment placement.

● Identify unsupported, end-of-life, incorrectly installed, or undocumented infrastructure.

● Identify capacity, resiliency, operational, and security gaps. 

● Produce clear recommendations for remediation and infrastructure improvement.

● Maintain accurate installed-device inventories as work progresses. 

Infrastructure Documentation 

Create, update, and maintain accurate infrastructure documentation, including: 

● Logical and physical network topology diagrams. 

● Rack elevation diagrams.

● Cabling and patching layouts. 

● Installed-device inventories. 

● IP addressing and VLAN documentation. 

● Network service dependencies. 

● Circuit and uplink documentation. 

● Power connectivity and redundancy information. 

● Migration plans, implementation records, and validation results. 

● Operational procedures and troubleshooting guidance. 

Documentation will primarily be maintained in Notion, with diagrams created in Lucidchart using a provided license. 

Rack and Cabling Improvements 

● Assist with planning and coordinating replacement racks and infrastructure improvements. 

● Review rack layouts, equipment placement, airflow, power distribution, and cable management. 

● Develop proposed rack elevation and cabling plans before implementation. 

● Coordinate with low-voltage, electrical, facilities, and other infrastructure vendors.

● Validate labeling, patching, cable routing, and installation quality. 

● Ensure that network equipment is installed in accordance with operational and manufacturer best practices. 

● Assist with remediation of legacy or poorly documented cabling. 

● Verify that completed work matches approved designs and documentation.

Power Infrastructure and Monitoring 

● Assist with bringing UPS and PDU infrastructure online. 

● Configure management connectivity, addressing, naming, and access.

● Integrate supported devices with SNMP-based monitoring systems. 

● Validate telemetry for power state, load, battery health, environmental conditions, and device status. 

● Configure or assist with alerting and reporting. 

● Confirm that monitoring data is accurate and actionable. 

● Document power dependencies and equipment connections. 

● Support testing of power redundancy and alerting where appropriate.

Operational Coordination

● Work closely with Network Engineering, IT, Security, Facilities, and other internal technical teams. 

● Coordinate with hardware, cabling, low-voltage, electrical, and other external vendors.

● Communicate risks, blockers, dependencies, and implementation status clearly. 

● Escalate issues promptly when they may affect migration timelines or service availability.

● Maintain accurate records of decisions, changes, and outstanding work. 

● Take ownership of assigned workstreams and drive them through completion. 

● Follow established change-management, security, and operational processes. 

Required Technical Competencies 

Core Networking 

● Strong understanding of networking fundamentals, including routing and switching. 

● Experience working with VLANs, subnetting, IP addressing, trunking, and Layer 2 and Layer 3 connectivity. 

● Experience troubleshooting network connectivity and performance issues. 

● Ability to interpret network diagrams, routing tables, ARP tables, MAC address tables, interface statistics, and packet-flow information. 

● Experience supporting network migrations and infrastructure changes. 

● Familiarity with network monitoring and operational troubleshooting tools. 

Switching 

● Hands-on experience configuring and troubleshooting enterprise network switches.

● Understanding of access and trunk port configuration, VLAN assignment, link aggregation, spanning tree, and uplink redundancy. 

● Ability to validate physical connectivity, optics, cabling, interface state, errors, and negotiated speed. 

● Cisco switching experience is preferred. 

Firewall Platforms 

● Experience supporting enterprise firewall environments. 

● Understanding of security policies, routing, NAT, zones, interfaces, and traffic-flow troubleshooting. 

● Experience with Palo Alto Networks firewalls is strongly preferred. 

● Familiarity with Panorama is beneficial. 

Network Services 

● Experience configuring and troubleshooting DHCP. 

● Strong understanding of DNS fundamentals and common resolution issues. ● Experience with IP address management tools and processes.

● Ability to maintain accurate subnet, VLAN, and addressing records. 

● Familiarity with SNMP-based infrastructure monitoring. 

Physical Infrastructure 

● Experience working in network and telecommunications rooms. 

● Understanding of network racks, structured cabling, patch panels, optics, UPS systems, and PDUs. 

● Ability to trace, validate, label, and document network cabling. 

● Familiarity with rack power, cooling, cable management, and equipment installation best practices. 

● Experience coordinating with low-voltage or facilities vendors is preferred.

Documentation 

● Ability to produce clear, accurate, and maintainable technical documentation.

● Experience creating logical and physical network topology diagrams.

● Experience producing rack elevation and cabling diagrams. 

● Ability to maintain infrastructure inventories and implementation records.

● Experience with Notion and Lucidchart is preferred. 

Required Experience 

● 5 or more years of professional experience in network engineering, network operations, or infrastructure engineering. 

● Demonstrated experience supporting enterprise routing and switching environments.

● Experience participating in network upgrades, migrations, or re-IP projects. 

● Experience troubleshooting network and firewall connectivity issues. 

● Experience working with physical network infrastructure, racks, cabling, and power systems. 

Preferred Qualifications 

● Cisco CCNA, CCNP, or equivalent practical experience. 

● Palo Alto Networks certification or substantial hands-on experience. 

● Experience with Cisco enterprise switching platforms. 

● Experience with Palo Alto Networks firewalls and Panorama. 

● Experience with an enterprise IPAM platform. 

● Experience with SNMP monitoring and infrastructure alerting.

● Familiarity with UPS and intelligent PDU management. 

● Experience working in office, campus, laboratory, manufacturing, or mixed-use technical environments. 

● Basic experience with network automation, scripting, APIs, or configuration-management tools is beneficial.