IT Network Engineer Allen, TX IT

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 is moving incredibly fast to develop and deliver advanced defense systems at a time when execution matters more than ever. We believe focus, ownership, and excellence are decisive advantages - and we're building a world-class team to turn bold ideas into real capability.

This is a rare opportunity to join at an early stage, where you'll have significant ownership, collaborate with exceptional teammates, and make a direct, measurable impact on our mission and the future of the company - regardless of your function.

We are seeking a highly skilledNetwork Engineerto implement, manage, and maintain network infrastructures supporting our mission-critical systems. The ideal candidate will bring deep technical knowledge of networking protocols and architecture, an understanding of cybersecurity requirements (e.g., DISA STIGs, hardening, zero trust), and proven experience operating in a fast paced, growing organization. This role will align well with a candidate experienced working in a manufacturing campus setting. An independent, autonomous self-starter personality is a must.

Responsibilities

• Design, deploy, and maintain secure and scalable enterprise network infrastructures, including LAN, WAN, VPN, VoIP, and wireless.
• Collaborate with network team lead, management, cybersecurity, and systems administration teams teams to enable and secure the corporate, OT, guest, and other networks
• Maintain modern hybrid cloud network infrastructure, including workloads on-premises, in major cloud providers, and in the field.
• Configure and manage routers, switches, firewalls, and other network devices from common major vendors.
• Implement and maintain system hardening in compliance with DoD STIGs, NIST frameworks, CMMC, and more.
• Perform troubleshooting and root cause analysis of complex network issues in a multitude of environments.
• Develop and maintain network documentation, diagrams, and standard operating procedures.
• Participate in audits, accreditation, and certification processes.
• Support deployments and field operations, including as-needed travel (5-10%) to other Castelion sites.

Basic Qualifications

• Bachelor’s degree in Computer Science, Information Technology, or a related field (or equivalent experience).
• 3+ yearsof experience in network engineering roles, preferably in fast-paced companies, startup, defense, or government environments.
• Strong knowledge of networking protocols (TCP/IP, BGP, OSPF, EIGRP, MPLS).
• Hands-on experience with hardware: firewalls, switches, wireless access points, and power.
• Experience applying controls as directed by cybersecurity frameworks (RMF, STIGs, NIST, CMMC).
• Strong documentation and communication skills.
• Strong experience with SD-WAN and software-defined networking (SDN).

Preferred Skills and Experience

• Industry certifications such asCompTIA Security+,CISSP,orCCNA.
• Experience with 802.1x and RADIUS for wired and wireless networks.
• Experience supporting classified networks.
• Experience with automation tools (Ansible, Terraform, Puppet, PowerShell DSC).
• Understanding of Zero Trust architecture and secure enclave designs.
• Active Security Clearance

Working Conditions

• On-site work; some after-hours/on-call support may be necessary.
• Occasional lifting of IT equipment (up to 40 lbs) and data center work.

• Castelion offers a generous benefits package. Please refer to the bottom of our Careers page for more details.

Other Duties

Please note this job description is not designed to cover or contain a comprehensive listing of activities, duties or responsibilities that are required of the employee for this job. Duties, responsibilities and activities may change at any time with or without notice.

Additional Eligibility Requirements

This position may require access to classified information or restricted U.S. Government sites, systems, or information, as determined by the Company and/or applicable U.S. Government requirements. If the position is so designated, your employment in the role may be contingent upon your ability to obtain and maintain the required U.S. Government security clearance or other government authorization, and to satisfy any citizenship or other eligibility requirements imposed by applicable law, regulation, executive order, or government contract requirements. You will be notified if and when such requirements apply.

Affirmative Action/EEO Statement

Castelion is an Equal Opportunity Employer. We are committed to providing equal employment opportunities to all applicants and employees without regard to race, color, religion, sex, sexual orientation, gender identity, national origin, age, disability, genetic information, protected veteran status, or any other characteristic protected by applicable federal, state, or local law.

Castelion is committed to providing reasonable accommodations to qualified individuals with disabilities throughout the application and hiring process. If you require a reasonable accommodation to complete an application, participate in the interview process, or otherwise participate in the hiring process, please contact [e-mail]. Requests for accommodation will be considered on an individual basis and handled in accordance with applicable law.

Castelion is committed to fostering a workplace where employment decisions are based on qualifications, business needs, and the ability to perform the essential functions of the role, with or without reasonable accommodation.

This position requires access to export-controlled information, and as such, employment (or hiring of a contractor) is contingent upon the candidate’s ability to access all applicable export-controlled information without additional export licensing being required by the Bureau of Industry and Security and/or the Directorate of Defense Trade Controls.