Defense Network Engineer – Secure, Hybrid Cloud Ops

Castelion Corporation; Allen (TX); On-site; USD 110,000 - 160,000; Full time

Job summary

Castelion Corporation in Texas is seeking a highly skilled Network Engineer to design, implement, and manage secure network infrastructures supporting our mission-critical systems on a fast-growing defense-focused campus.

You will collaborate with cybersecurity, systems, and management to harden networks per RMF, STIGs, and CMMC, while supporting hybrid cloud environments and field deployments. On-site with occasional travel; strong documentation and communication required.

Qualifications

• Bachelor’s degree in Computer Science, Information Technology, or related field or equivalent experience.
• 3+ years in network engineering, preferably in defense/government environments.
• Strong knowledge of TCP/IP, BGP, OSPF, EIGRP, and MPLS.
• Hands-on experience with firewalls, switches, wireless APs, and power.
• Experience with cybersecurity controls (RMF, STIGs, NIST, CMMC).
• Excellent documentation and communication skills.
• Experience with SD-WAN and SDN.

Responsibilities

• Design, deploy, and maintain secure, scalable enterprise network infrastructures (LAN/WAN/VPN/VoIP/Wi‑Fi).
• Collaborate with network, cybersecurity, and systems teams to secure corporate and OT networks.
• Maintain hybrid cloud networks across on‑premises and major cloud providers.
• Configure routers, switches, firewalls, and other network devices from major vendors.
• Implement system hardening per DoD STIGs and NIST/CMMC.
• Troubleshoot complex network issues across environments.
• Create and maintain network documentation and SOPs.
• Support audits, accreditation, and certification processes.
• Travel (5–10%) to other Castelion sites.

Skills

3+ years experience

SD-WAN

SDN

Network security

Documentation

Strong communication

Education

Bachelor's in CS/IT

Tools

Firewalls

Switches & Routers

Wireless APs

VPN

Automation tools (Ansible, Terraform, Puppet, PowerShell DSC)

Job description

Castelion Corporation in Texas is seeking a highly skilled Network Engineer to design, implement, and manage secure network infrastructures supporting our mission-critical systems on a fast-growing defense-focused campus.

You will collaborate with cybersecurity, systems, and management to harden networks per RMF, STIGs, and CMMC, while supporting hybrid cloud environments and field deployments. On-site with occasional travel; strong documentation and communication required.