Senior Network Engineer III – Enterprise Networking

JMARK Business Solutions, Inc.; Tulsa (OK); On-site; USD 80,000 - 115,000; Full time

Job summary

JMARK Business Solutions, Inc. is seeking a Network Engineer III to join our Tulsa team. You will maintain and improve complex enterprise networks, primarily for a large banking client, ensuring security, reliability and performance across critical infrastructure.

The role involves hands-on work with advanced networking technologies, troubleshooting complex issues, and owning infrastructure in a high-availability environment. Banking experience is a plus but not required.

Qualifications

• 3–5 years or more of relevant network engineering experience.
• Advanced knowledge of enterprise networking technologies (LAN/WAN, routing, switching, security).
• Experience configuring and troubleshooting Cisco networking equipment or comparable enterprise networking technologies.
• Experience with routing protocols: OSPF, BGP, EIGRP.
• Advanced understanding of VLANs, STP, subnetting, IPv4/IPv6.
• Experience implementing, administering and troubleshooting firewalls, VPNs, and secure connectivity.
• Familiarity with Cisco ASA, Fortinet or similar firewalls.
• Experience using network monitoring and troubleshooting tools such as Wireshark and SSH.
• Understanding of network security principles, access controls, intrusion prevention.

Responsibilities

• Maintain, troubleshoot, secure, and improve complex network environments.
• Work with engineers and client stakeholders to ensure network performance.
• Network Infrastructure Management: configure, maintain, troubleshoot, optimize networking tech.
• Advanced Troubleshooting: act as escalation point for complex issues and root cause analysis.
• Network Security: maintain secure infrastructure incl. firewalls and secure access.
• Routing & Switching: configure VLANs, STP, routing protocols and segmentation.
• Proactive Network Management: monitor health and propose improvements.
• Project Implementation: participate in upgrades, migrations, deployments.
• Documentation & Collaboration: maintain docs and communicate with teams and clients.
• Technical Leadership: mentor engineers and share knowledge.

Skills

Cisco networking

Network security

Troubleshooting

OSPF/BGP/EIGRP

VLANs & STP

Firewall & VPN

Documentation

Tools

Wireshark

SSH

Cisco IOS

Job description

JMARK Business Solutions, Inc. is seeking a Network Engineer III to join our Tulsa team. You will maintain and improve complex enterprise networks, primarily for a large banking client, ensuring security, reliability and performance across critical infrastructure.

The role involves hands-on work with advanced networking technologies, troubleshooting complex issues, and owning infrastructure in a high-availability environment. Banking experience is a plus but not required.