Seeking an experienced IT systems administrator to support our San Diego, CA classified lab environments with expertise in setting up and managing Windows and Linux based systems and Virtual Machines. A successful candidate will be a well-rounded administrator joining a team supporting internal customers, designing, implementing, and managing lab infrastructure to meet the customer requirements. In this role, you will build, configure, administer, and troubleshoot Windows, Linux, and VM servers/workstation hardware and software. • Support the design and implementation of workgroup-scale networks, build and manage authentication, file-share, and other collaboration servers to support groups of heterogeneous client systems. • Work with industrial security to develop and apply hardening configurations for systems for classified use to RMF requirements; Document system configuration for new and existing systems; Experience with centralized authentication technologies such as LDAP and Active Directory domains in supporting Windows/Linux cross-platform clients is desirable. • willing to respond to occasional off-hours outages and take part in subsequent service restoration efforts. This is not inclusive of all job duties. • Maintains operation of multi-user computer systems, including coordination with network engineers. • Duties may include setting up administrator and service account, maintaining system documentation, turning system performance, installing system wide software, and allocate mass storage space. • Makes recommendations to purchase hardware and software, coordinates installation, and provides backup recovery. • Develops and monitors policies and standards related to the use of computing resources. • CompTIA Security+ (or equivalent) and a TS/SCI Clearance will be required to work in the environment. This position will be posted for at least 5 calendar days. The posting will remain active until the position is filled, or a qualified pool of candidates is identified. Required Skills and Education • US Citizenship. • Active U.S. Top Secret Security Clearance with SCI eligibility and CompTIA Security+ or equivalent DoD 8570 IAT Level II certification. • 5-7 years of experience (4+ years of experience with a degree) as a system administrator. • Direct experience configuring and managing Lab-in-a-Box (LIB) environments. • Familiarity with data spill response protocols and secure system sanitization. • Hands-on experience with Nessus, VMware vSphere, Veeam, and Trellix ePO. • Strong Active Directory experience, including domain controller and GPO management. • Working knowledge of Splunk in secure environments (including alerting and data retention strategies). • Understanding of DoD and IC security standards, including RMF, NISPOM, and STIG compliance. Preferred Skills and Education • Active U.S. TS/SCI Security Clearance. • 4+ years of experience working in a classified environment • Experience with system accreditation (e.g., SSP development, POA&M tracking). • Familiarity with classified lab setups, test bed environments, or R&D support. • Exposure to cross-domain solutions, enclave management, or SAP/SAR environments. / • Scripting experience (PowerShell, Python) to automate common sysadmin tasks. • Experience supporting audit and inspection activities