Linux Systems Administrator (DoD/IC Security)

KEITH A. LEE

TS/SCI with CI Poly • Security+ CE

667-***-**** • ********@*****.***

SUMMARY

Linux Systems Administrator with extensive experience securing, maintaining, and modernizing classified enterprise environments within DoD and IC missions. Over 15+ years supporting Red Hat, Windows Server, Sybase environments, cross-domain solutions, and secure system architectures across multi-domain networks. Proven background operating under NISPOM, RMF, STIG, ICD 503, and other security frameworks. Recognized for independently resolving complex technical issues, executing system enhancements, developing automation, and collaborating with security, engineering, and mission teams.

CORE COMPETENCIES

Windows Server Administration

Linux (RHEL 7/8) Administration

STIG Compliance / RMF / ICD 503 / NISPOM Ch. 8

System Deployment

Bash Scripting

Multi-domain network support

SQL Server, Sybase ASE,

Backup/Recovery & Patch Management

Security Hardening / PKI Integration

AWS (EC2, volumes, Linux/Windows instances)

Incident Response & Troubleshooting

Splunk Monitoring

Change/Configuration Management (Service Central)

PROFESSIONAL EXPERIENCE

TIA Cyber Academy

CEO and Technical trainer

January 2021 – Present

Taught Cyber Security Fundamentals, Securing Windows Operating System, Comptia Security + preparation course, and Linux Operating System Fundamentals.

Peraton Corporation

Senior Cyber Systems Administrator

March 2025 – November 2025

Maintain and administer Red Hat 8 VMs and AWS instances supporting MIDB and IC mission systems, ensuring secure operational uptime

Troubleshoot firewalls, F5, FIPS, and permissions issues across multi-domain environments.

Manage FTP server user accounts; support Sybase replication resolution for MIDB.

Assist in building AWS Oracle 8 servers, including PHP, Postgres, OS partitions, and volume configuration.

Monitor and analyze system performance using Splunk; submit change requests via Service Central.

Senior Cyber Systems Administrator

March 2023 – January 2025

Administered 10+ Windows Server 2016 systems including SQL Server databases across two domains —directly aligning to Northrop Grumman’s Windows domain administration requirements

Prepared agency servers for CCRI inspections, ensuring full STIG compliance.

Managed Red Hat 7 servers across three domains; maintained Jive application and services.

Supported MIDB Linux/Windows infrastructure, troubleshooting replication and application issues.

Senior Cyber Systems Administrator / Program Manager

February 2021 – March 2023

Managed RHEL 7 VMs, performed software builds, Sybase ASE installs, PKI enablement, and corrective/preventive maintenance.

Maintained ISSE Guard, MLDBR servers, and cross-domain solution environments.

Led a global collaboration program using Jive; supervised seven systems administrators and ensured successful system upgrades and maintenance.

Delivered technical mentorship and process documentation.

Northrop Grumman

Engineering & Science Manager Database/Sr. Systems Administrator

February 2013 – January 2021

Designed, operated, and troubleshot complex Linux, Solaris, and Oracle environments including Red Hat 6.8 VMs and Sunfire platforms

Supported global MIDB customers, resolving complex server issues on Solaris, RHEL, and virtual machines.

Performed Sybase ASE and MIDB installs/upgrades; ensured PKI integration.

Maintained ISSE Guard and MLDBR cross-domain solution systems.

Provided leadership on engineering projects, coordinating across security, network, and systems teams—experience directly aligned with Northrop’s requirement for cross-team coordination and independent work

.

WCIL – Database/Systems Administrator

October 2008 – February 2012

Maintained 100+ Oracle servers, Solaris zones, and related infrastructure.

Performed software builds, Sybase installs, WebLogic configuration, PKI setup, and OS upgrades.

Resolved complex issues across Solaris 8/10/11 environments, Sunfire systems, and cross-domain solutions.

EDUCATION & CERTIFICATIONS

Master of Science – Network Security (2006)

Bachelor of Science – Business Administration (2001)

CompTIA Security+ CE (meets DoD 8140 requirement)

AWS Certified Cloud Practitioner

Technical Courses: VMware Infrastructure 3, Linux+, Sybase ASE Admin, Windows 2000 Security, Cisco Router Troubleshooting, Solaris Administration, Shell Scripting, Network Security, and others

RELEVANT SKILLS FOR THIS ROLE

Windows Server OS management, Active Directory, GPOs (from CWS Windows 2016 server administration)

VMware experience through multiple virtualization environments, Linux/Unix VM builds, and enterprise deployments (aligned to NG VMware requirements)

RMF, STIG, NISPOM, ICD 503 secure system operations across DoD/IC networks

Backup and recovery procedures, file system management

User and computer account administration, permissions and access list management

Documentation of technical processes and security practices

Ability to lift 40 lbs, work after hours/weekends (role requirement)

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