Senior Network Engineer Security Clearance

Position: Senior Network Engineer with Security Clearance
Job Type: Full
- Time Workplace Type:
Onsite Clearance: TS/SCI Must be a U.S. Citizen Benefits:
Medical, dental, and vision coverage, 401k matching, generous PTO, paid holidays, professional training opportunities, and even pet insurance to ensure your furry friends are cared for too.

Job Summary Castalia Systems is seeking a Senior Network Engineer for a position in Largo, Florida. Due to the applicable duties, this position requires 100% onsite employee status. The Network Engineer position implements network security and information assurance solutions for program and development systems based upon system level requirements, architecture models, and engineering design documents using a defense-in-depth approach on trusted products.

This position will involve maintenance, installation, testing, and general support for network infrastructure. The ability and know-how to do basic/advanced troubleshooting, including testing during and after implementation. A solid understating of networking fundamentals is required, and how these fundamental technologies are used in a LAN, MAN or WAN architecture.

Roles and Responsibilities A qualified candidate will perform the following duties and responsibilities, but are not limited to:
* Configure, administer, and maintain Cisco Unified Communications Manager (CUCM) clusters supporting enterprise and classified environments.
* Manage and maintain Cisco Unity Connection voicemail systems, including user provisioning, call handlers, automated attendants, and voicemail integrations.
* Configure and support dial plans, route patterns, route groups, route lists, SIP trunks, device pools, partitions, and calling search spaces.
* Administer and troubleshoot voice gateways, session border controllers, and VoIP infrastructure.
* Provide Tier III technical support, troubleshooting complex voice, call routing, registration, signaling, and voice quality issues.
* Design, implement, and maintain hunt pilots, hunt lists, line groups, call queuing, and call coverage solutions to optimize call distribution and operational workflows.
* Configure, manage, and support Meet-Me conferencing services, conference bridge resources, and collaboration platforms.
* Plan, coordinate, and execute CUCM and Unity Connection upgrades, patches, and lifecycle management activities.
* Develop upgrade runbooks, rollback procedures, testing plans, and maintenance schedules to ensure successful system implementations.
* Deploy, configure, and integrate Uni Fi FX solutions within enterprise communications environment.
* Support migration planning, testing, validation, and production cutover activities for voice and collaboration modernization initiatives.
* Implement and maintain DISA Security Technical Implementation Guide (STIG) compliance for Cisco Unified Communications platforms and associated virtual appliances.
* Perform vulnerability remediation, security hardening, compliance validation, and support cybersecurity audits, inspections, and accreditation activities.
* Maintain secure communications environments in accordance with DoD, organizational, and cybersecurity requirements.
* Develop and maintain engineering diagrams, configuration standards, operational procedures, disaster recovery plans, and technical documentation.
* Create, document, and defend system change requests while ensuring configuration management compliance.
* Conduct root cause analysis, incident response activities, and corrective actions to improve system reliability and performance.
* Collaborate with cybersecurity, network, infrastructure, and business stakeholders to implement and support enterprise communication services.
* Gather, analyze, and report system performance metrics to support operational readiness, capacity planning, and continuous improvement initiatives.
* Provide technical guidance and mentorship to junior engineers and support personnel.
* Contribute to strategic modernization efforts and the design, architecture, and enhancement of enterprise voice and collaboration platforms.

Required Qualifications:

* Bachelor’s degree and 12 months of relevant professional work experience (excluding internships)
* In absence of a degree, 6 years of relevant experience is required
* Must be able to attain and maintain a DoD 8570 IAT Level II certification (Security+ or CISSP preferred).
* A strong understanding and knowledge of computer, network, and security systems.
* Good interpersonal and communication skills.
* Strong analytical, critical thinking, and problem-solving skills.
* Ability to work well independently under limited oversight, be self-directed and able to prioritize work.

Preferred Qualifications:

* Experience with Juniper SRX, EX series routers and switches.
* Experience deploying security solutions for DoD networks.
* Experience with multi-platforms like Windows, UNIX, LINUX
* Understanding of network engineering fundamentals, including: OSI layers, IP addressing, sub-netting, TCP/IP stack, VLANs, DHCP,…