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Agent guide: [/agents.md](https://www.wearedevelopers.com/agents.md). --- # System Administrator - **Company:** Def-Logix, Inc - **Location:** San Antonio, TX, United States - **Experience:** Experienced - **Contract:** Permanent contract - **Skills:** Microsoft Windows, Active Directory, Backup Devices, Bash Shell, Microsoft Online Services, Configuration Management, Cyber Security, Dynamic Host Configuration Protocol, Linux, Network Address Translation, Domain Name System (DNS), VMware ESX Servers, Subnetting, Virtual Private Networks (VPN), Python (Programming Language), Linux Servers, Microsoft Security Essentials, Microsoft Software, Windows Servers, Routing, Network Segmentation, OpenVPN, Windows PowerShell, Azure Active Directory, Kusto Query Language, Microsoft SharePoint, TCP/IP, Virtual Local Area Networks, Virtual Machines, Virtualization Technology, VMware VSphere, Software Vulnerability Management, Data Logging, Software Troubleshooting, Firewalls (Computer Science), Gitlab, Microsoft InTune, PfSense, Network Server, Cisco, Vmware - **Published:** July 5, 2026 - **Apply:** https://www.indeed.com/viewjob?jk=e0aa04aca6d100d8 ## About the Role * 3+ years of hands-on systems administration or advanced infrastructure support experience in production environments. * Strong TCP/IP, DNS, DHCP, subnetting, routing, VLAN, NAT, VPN, firewall, Windows/AD, Linux, and virtualization fundamentals. * Experience administering Microsoft 365; Microsoft security operations experience is strongly preferred. * Demonstrated ability to troubleshoot independently, document changes, validate results, and use safe rollback procedures. * Ability to work onsite, perform physical IT support, and handle CUI and sensitive information under applicable requirements., * Direct experience with pfSense, OpenVPN, Cisco, UniFi, VMware vSphere, and GitLab. * Experience with Microsoft Entra ID, Conditional Access, Intune, Exchange Online, Defender XDR, Sentinel, and KQL. * Experience supporting segmented, regulated, government-contractor, defense-industry, or other security-sensitive environments. * Working knowledge of CUI, CMMC Level 2, NIST SP 800-171, DFARS 252.204-7012, access-control evidence, and compliance documentation. * Experience maintaining system security plans, configuration baselines, inventories, diagrams, remediation records, and audit evidence. * PowerShell, Bash, Python, or other scripting and automation experience. * Relevant certifications such as Security+, Network+, CCNA, Microsoft, VMware, or Linux certifications, or equivalent demonstrated experience. ## Description We are seeking a hands-on Systems Administrator to support a mixed Windows, Linux, virtualization, networking, Microsoft 365, and cybersecurity environment. This role combines production systems administration with onsite user support and requires the ability to troubleshoot across workstations, servers, identity, networks, VPNs, and security tooling. The environment includes multiple segmented networks, including corporate, development/sandbox, cloud-connected, and restricted CUI systems. The administrator will help manage and security-monitor a CMMC Level 2 self-assessed environment and maintain the controls, records, and operational discipline needed to support NIST SP 800-171 requirements., * Administer Windows Server, Active Directory, Group Policy, DNS, DHCP, permissions, and routine identity lifecycle tasks. * Manage VMware vSphere/ESXi, Linux servers, virtual machines, storage, patching, backups, certificates, logs, and service troubleshooting. * Configure and support pfSense, OpenVPN, Cisco and UniFi switching, VLANs, routing, NAT, firewall policy, wireless, and network segmentation. * Administer the primary Microsoft 365 tenant and smaller tenants, including Entra ID, Exchange Online, Teams, SharePoint, licensing, MFA, and Conditional Access. * Triage and investigate Microsoft Defender XDR and Sentinel alerts; collect evidence, contain, remediate, document, or escalate incidents. * Manage and security-monitor the CUI environment, including access control, logging, vulnerability remediation, configuration management, and compliance evidence. * Provide onsite helpdesk support, workstation deployment, onboarding/offboarding, cabling, hardware replacement, and equipment inventory. * Support GitLab and development infrastructure, including access, availability, backups, certificates, and basic service troubleshooting. ## Related Videos - [An Applied Introduction to eBPF with Go](https://www.wearedevelopers.com/videos/1075-an-applied-introduction-to-ebpf-with-go) - [How Cisco embraced a DevOps culture within its network engineering team](https://www.wearedevelopers.com/videos/99-how-cisco-embraced-a-devops-culture-within-its-network-engineering-team) - [Security Pitfalls for Software Engineers](https://www.wearedevelopers.com/videos/726-security-pitfalls-for-software-engineers) - [Docker network without Docker](https://www.wearedevelopers.com/videos/1418-docker-network-without-docker) - [Turning Container security up to 11 with Capabilities](https://www.wearedevelopers.com/videos/718-turning-container-security-up-to-11-with-capabilities) - [Your Infrastructure Is Not a Playground: AI Agents for Infra Done Right](https://www.wearedevelopers.com/videos/2084-your-infrastructure-is-not-a-playground-ai-agents-for-infra-done-right) ## Related Articles - [How We Built a Worry-Free System That Runs for 10+ Years – And What We’d Do Again](https://www.wearedevelopers.com/magazine/751-how-we-built-a-worry-free-system-that-runs-for-10-years-and-what-we-d-do-again) - [What Are The Top Skills Required For Azure Developers?](https://www.wearedevelopers.com/magazine/77-what-are-the-top-skills-required-for-azure-developers) - [The Most Popular IT Jobs on the Market](https://www.wearedevelopers.com/magazine/376-the-most-popular-it-jobs-on-the-market) - [Dev Digest 134 - Where pixels sing?](https://www.wearedevelopers.com/magazine/477-dev-digest-134-where-pixels-sing) - [Top-Paying Tech Jobs (with Salaries)](https://www.wearedevelopers.com/magazine/372-top-paying-tech-jobs-with-salaries) - [What’s the Difference between a Junior, Mid, and Senior Developer?](https://www.wearedevelopers.com/magazine/238-what-s-the-difference-between-a-junior-mid-and-senior-developer)