Years in Cybersecurity and Network Engineering
Hands-on work securing, administering, and supporting enterprise technology environments across federal agencies and the Department of Defense.
Cybersecurity and Network Security · CompTIA Security+ · CompTIA CySA+
Keijon
Miller
// Network Engineer · Information Security · NIST RMF, FISMA, and ATO
Keijon is a cybersecurity, network engineering, and information systems professional with more than seven years of experience securing, administering, and supporting enterprise technology environments across federal agencies and the Department of Defense. He earned CompTIA Security+ and CompTIA CySA+ through Accumentum and has supported mission environments associated with the U.S. Army Intelligence and Security Command (INSCOM), the Department of the Treasury (IRS), Naval Air Systems Command (NAVAIR), and the Federal Emergency Management Agency (FEMA). His work includes enterprise LAN/WAN architecture, network security, Cisco Identity Services Engine (ISE), NIST Risk Management Framework (RMF), FISMA compliance, and Authority to Operate (ATO) support.
CompTIA Security+ CompTIA CySA+ Network Engineer Federal and DoD Mission Systems Washington DC-Baltimore Area
7+Years securing and supporting enterprise technology environments
4Federal and DoD mission environments, including INSCOM, IRS, NAVAIR, and FEMA
2CompTIA credentials earned with Accumentum, Security+ and CySA+
3 yr 1 moCurrent Jacobs role supporting U.S. Army INSCOM operations at Fort Belvoir
// 01
By the Numbers
Federal and DoD Mission Environments
Supported organizations and mission environments associated with INSCOM, the Department of the Treasury (IRS), NAVAIR, and FEMA.
CompTIA Credentials with Accumentum
Earned CompTIA Security+ in February 2026 and CompTIA CySA+ in November 2026 through Accumentum.
Current INSCOM Support Role
Serves as a Network/System Administrator II and Night Shift Watch Analyst at Jacobs, supporting U.S. Army INSCOM operations at Fort Belvoir, Virginia.
// 02
Operational Highlights
Mission-Critical Network and Systems Support
At Jacobs, provides Tier 2 network and systems administration support for U.S. Army INSCOM customers. He serves as an overnight watch analyst, monitoring availability with WhatsUp Gold, managing incidents through Remedy, and supporting Cisco, Juniper, and network security infrastructure.
Tier 2 Support WhatsUp Gold Remedy Cisco and Juniper
Federal Information Security at the Treasury
As an IT Specialist (INFOSEC) for the U.S. Department of the Treasury, supported enterprise information security operations for the IRS. This included vulnerability assessments, FISMA and NIST SP 800-53 reviews, privileged access controls, and protection of SBU information and PII.
FISMA NIST SP 800-53 Access Control PII Protection
Enterprise Network Engineering and Authorization
At Phia, engineered and secured enterprise network infrastructure, administered Cisco ISE, and led Authority to Operate processes. He also supported SCIF infrastructure builds, SolarWinds monitoring, and security documentation including SSPs and SARs.
Cisco ISE ATO SolarWinds SCIF Infrastructure
Aviation Program Security and Network Engineering
At MANTECH, supported the PMA-228 aviation program as a Network Engineer and Information Systems Security Manager. He maintained LAN and WAN infrastructure, supported ATO documentation, configured TACLANE encryption devices, and analyzed network and security data with Splunk.
NAVAIR TACLANE Splunk RMF Documentation
// 03
Experience
Nov 2023 to Present
Network and Systems Administration
Network/System Administrator II · Night Shift Watch Analyst
Jacobs · Fort Belvoir, Virginia
- Provides Tier 2 network and systems administration support for U.S. Army Intelligence and Security Command (INSCOM) customers, supporting the stability, security, and operational availability of mission-critical communications infrastructure.
- Serves as an overnight watch analyst responsible for network monitoring, troubleshooting, operational assessments, and technical coordination across complex enterprise technology environments.
- Configures, troubleshoots, and supports Cisco routers and switches, Juniper networking equipment, Dell workstations, Sun servers, inline encryption devices, and network security appliances.
- Monitors network availability, performance, and stability using WhatsUp Gold, and manages incidents, service requests, and technical documentation through Remedy.
- Participates in deployment planning, site assessments, vulnerability assessments, operational scenario evaluations, and Concept of Operations (CONOPS) development.
- Prepares shift turnover documentation, operational status reports, technical findings, and leadership briefings to support continuity between operational teams.
Nov 2023 to Sep 2025
Information Security
IT Specialist (INFOSEC)
U.S. Department of the Treasury · New Carrollton, Maryland
- Supported enterprise information security operations for the Internal Revenue Service (IRS), focusing on protecting critical federal IT infrastructure, strengthening access controls, evaluating security risks, and maintaining alignment with federal cybersecurity requirements.
- Conducted vulnerability assessments and penetration testing activities to identify cybersecurity threats, evaluate technical weaknesses, and recommend mitigation measures.
- Assessed information systems against Federal Information Security Modernization Act (FISMA) requirements and NIST SP 800-53 security controls, and conducted Tier I to III security accreditation reviews.
- Supported the protection and appropriate handling of Sensitive But Unclassified (SBU) information and Personally Identifiable Information (PII).
- Evaluated authentication technologies, including smart card authentication and biometric security solutions, to support secure identity verification and access management.
- Updated and maintained contingency planning and disaster recovery documentation, and planned IT security awareness training initiatives for personnel across organizational levels.
Dec 2022 to Nov 2023
Network Engineering · ATO
Network Engineer
Phia · Suitland, Maryland
- Engineered, deployed, maintained, and secured enterprise network infrastructure supporting federal technology environments, combining hands-on network engineering with security authorization, access control, incident response, and continuous monitoring.
- Led Authority to Operate (ATO) processes for systems, projects, and networks, supporting security documentation, assessment activities, and authorization requirements.
- Administered and maintained Cisco Identity Services Engine (ISE), including troubleshooting, system optimization, patching, and role-based access control (RBAC) policy implementation.
- Configured and supported enterprise network technologies involving OSPF, TCP/IP, VLANs, and DHCP, and monitored network health with SolarWinds.
- Investigated network security incidents, resolved complex Tier 3 network issues, and supported Sensitive Compartmented Information Facility (SCIF) infrastructure builds.
- Developed and maintained System Security Plans (SSPs), Security Assessment Reports (SARs), and supporting security documentation, and coordinated remediation and continuous monitoring following ATO authorization.
Sep 2021 to Jun 2022
Network Engineering · Security Authorization
Network Engineer · Information Systems Security Manager (ISSM)
MANTECH · Lexington Park, Maryland
- Provided network engineering and information systems security management support for the PMA-228 aviation program, integrating enterprise infrastructure engineering with cybersecurity risk management and security authorization.
- Engineered, installed, configured, and maintained LAN and WAN infrastructure supporting aviation program environments, from initial deployment through ongoing administration.
- Managed security authorization documentation and supported Authority to Operate activities, including System Security Plans (SSPs), Security Assessment Reports (SARs), and Plans of Action and Milestones (POA&Ms).
- Configured and maintained TACLANE encryption devices, including firmware upgrades, enclave routing configurations, and device security settings.
- Administered Cisco Identity Services Engine (ISE) capabilities, including device profiling, posture assessment, guest access policies, and supporting technical documentation.
- Analyzed network and security data using Splunk to support technical investigations, system performance assessments, and security visibility.
Mar 2020 to Sep 2021
Systems Administration · Information Security
Systems Administrator · Information Security Associate
MANTECH · Lexington Park, Maryland
- Provided systems administration, information security, and infrastructure management support for the PMA-228 aviation program, contributing to secure and reliable enterprise IT operations.
- Conducted infrastructure and application risk assessments to identify vulnerabilities, evaluate potential security exposures, and support mitigation planning.
- Performed vulnerability scanning activities and supported the evaluation of technical findings and security concerns.
- Developed and maintained information security program components aligned with program objectives and operational security requirements.
- Supported Naval Air Systems Command (NAVAIR) IT asset strategy, infrastructure planning, and technology budgeting activities.
- Coordinated system installation, configuration, and technical support activities with security teams, operations personnel, and end users.
Aug 2019 to Mar 2020
Enterprise IT Support
Computer Specialist II
FEMA · Washington, District of Columbia
- Provided enterprise IT systems and infrastructure support for the Federal Emergency Management Agency (FEMA), including technology operations associated with the National Response Coordination Center.
- Conducted system optimization activities, resource utilization assessments, and capacity analyses to support efficient enterprise technology operations.
- Monitored Microsoft Active Directory environments and directory consolidation servers to support directory infrastructure and system administration activities.
- Maintained server racks, network equipment, and associated IT infrastructure within the FEMA National Response Coordination Center.
- Supported employee onboarding through IT system setup, technical configuration, and user support activities, and provided technical assistance for remote operations and emergency-response-related IT requirements.
// 04
Credentials and Qualifications
CompTIA
Cybersecurity Analyst (CySA+)
CompTIA CySA+ earned in November 2026 after Computer and Information Systems Security / Information Assurance training with Accumentum.
CompTIA
Security+
CompTIA Security+ earned in February 2026 after Computer and Information Systems Security / Information Assurance training with Accumentum.
// 05
Technical Skills
// Network
Network Engineering
LAN/WAN Architecture Routing and Switching Cisco and Juniper Cisco ISE OSPF VLANs DHCP TACLANE
// Security
Information Security and Risk
NIST RMF FISMA Authority to Operate Security Control Assessments Vulnerability Assessments Incident Response Privileged Access Management Continuous Monitoring
// Operations
Platforms and Operations
SolarWinds Splunk VMware Linux WhatsUp Gold Remedy Systems Administration Active Directory
// 06
Let’s Put Keijon To Work
Best aligned for network engineering, information security, risk management, and federal or DoD mission systems roles that need a Security+ and CySA+ certified professional with hands-on enterprise and mission-systems experience.
LinkedIn: linkedin.com/in/keijon-miller
Location: Washington DC-Baltimore Area
Current: Network/System Administrator II, Jacobs
// 07
Education
Accumentum®
CompTIA Cybersecurity Analyst (CySA+)
Computer and Information Systems Security / Information Assurance training with Accumentum in November 2026.
Accumentum®
CompTIA Security+
Computer and Information Systems Security / Information Assurance training with Accumentum in February 2026.
Strayer University
Strayer University
Attended from 2015 to 2019.
// Next Step
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