LEONARD Sheffield
Englewood ,Ohio
Summary
Hands-on network and systems specialist supporting enterprise infrastructure across routing, switching, firewalls, VMware, Windows Server, and Linux. Delivers secure access control, performance monitoring, backup and recovery support, and automation through scripting to help maintain stable operations.
Overview
1
1
Certification
9
9
years of professional experience
Work History
Network Engineer
Applied Research Solutions
Dayton, Ohio
05.2023 - Current
- Configured Cisco routers and switches across enterprise network environments
- Configured, monitored and maintained core networking equipment including Cisco routers, switches and firewalls.
- Troubleshot routers, switches, firewalls, and wireless access points.
- Resolved routing, switching, and connectivity issues for users and systems
- Monitored network performance using Cisco IOS and troubleshooting tools
- Configured VLANs for segmenting different parts of the network for better security and reliability.
- Configured network services such as DNS, DHCP, FTP, SSH, NFS.
- Set up user accounts, groups, and permissions for secure access control.
- Managed Active Directory, Group Policy, and access permissions for Air Force personnel.
- Managed Active Directory accounts, groups, and permissions across business systems.
- Managed Active Directory accounts, groups, and user permissions.
- Supported Linux server administration across production and development environments.
- Installed, configured, maintained and upgraded Linux operating systems and services.
- Configured and updated Linux servers with the latest releases and patches.
- Executed backups of critical systems to ensure data integrity and availability. and helped with restore and disaster recovery procedures.+
- Applied security patches and coordinated routine maintenance across production servers.
- Installed firmware updates on network equipment such as Cisco switches and routers.
- Automated processes through scripting languages such as Python or Bash Shell Scripting.
- Developed scripts using Python, SQL, JavaScript, Shell scripting languages for automation purposes.
- Troubleshot hardware, software malfunctions on a variety of platforms including Windows Server 2008, 2012 R2, 2016, Linux, Cisco IOS devices.
- Reviewed network diagrams and updated infrastructure records
- Documented network diagrams, configurations, and change requests.
- Deployed and managed networking equipment including routers, switches, and firewalls.
- Facilitated efficient inventory management by coordinating stocking and ordering activities.
- Participated in physical inventory counts to keep information accurate and current.
- Trained new staff on inventory procedures and system use.
- Managed inventory records using ERP and barcode scanning systems.
- Developed innovative solutions that improved team collaboration and project outcomes.
- Resolved technical issues for users, enhancing customer satisfaction through knowledgeable service.
- Worked successfully with a diverse group of coworkers to accomplish goals and address issues related to our products and services.
- Supported help desk requests for Air Force users and technical issues.
- Enforced cybersecurity controls and account security across Air Force information systems.
- Provisioned virtual machines using approved templates and change requests.
- Managed VMware ESXi hosts across enterprise data center environments.
- Configured vCenter Server, clusters, datastores, and virtual networks.
- Upgraded existing hardware to ensure compatibility with new versions of VMware products.
- Provided technical expertise in the installation, configuration and maintenance of VMware ESXi and vSphere environments.
- Administered Windows Server environments for enterprise operations and user support.
- Administered Windows servers and desktop systems across enterprise environments.
- Configured Spanning Tree Protocols on Cisco Catalyst Switches to prevent loops within the network infrastructure.
- Configured, monitored and maintained core networking equipment including Cisco routers, switches and firewalls.
- Managed Active Directory accounts, groups, and user permissions.
- Administered Windows servers and desktop systems across enterprise environments.
- Administered VMware vSphere clusters for enterprise server environments.
- Provisioned virtual machines across ESXi hosts and datastores.
- Configured virtual networking, storage, and access controls.
- Created and maintained virtual machines using vCenter Server.
- Configured VLANs for secure communication between physical networks and virtual machines.
- Managed multiple vCenters with high availability clusters including host, storage and network components.
System Administrator
Air Force
Wright Patterson, Ohio
12.2020 - 06.2022
- Led IT infrastructure planning and implementation projects, successfully migrating entire IT infrastructure, active directory, and network.
- Increased system security and performance with proactive change.
- Orchestrated and oversaw upgrades to system hardware and software.
- Delivered reliable support for server-class systems.
- Performed data backups and disaster recovery operations.
- Resolved issues and escalated problems, delivered knowledgeable support and quality service to enhance user experience.
- Administered user profiles and managed security access for shared file structures.
- Installed security software to protect networks.
- Determined and alleviated hardware, software and network issues.
- Set up user accounts, permissions and passwords and define network policies and procedures.
- Maintained comprehensive records, logs, and lifecycle documentation for work requests to ensure organized tracking and accountability.
- Promoted high customer satisfaction by resolving problems with knowledgeable and friendly service.
- Maintained composure and patience in the face of difficult customer situations, applying de-escalation techniques and positive customer support.
- Assisted customers by troubleshooting and resolving technical problems.
- Provided excellent service and attention to customers when face-to-face or through phone conversations.
- Kept customers informed about issue resolution progress and provided updated estimated times of resolution on an ongoing basis.
- Processed high volume of phone calls, chat, and emails to support DOD systems.
- Worked with customer service supervisors to resolve customer concerns on a daily basis.
- Prioritized and organized tasks to accomplish service goals efficiently accomplish service goals.
- Worked successfully with a diverse group of coworkers to accomplish goals and address issues related to our products and services.
- Demonstrated leadership by making improvements to work processes and helping to train others.
- Analyzed and interpreted policies, legislation and public issues on behalf of Administrator groups.
Cyber Systems Operator
Air Force
Salt Lake City, Utah
12.2017 - 12.2020
- Established user accounts, permissions, and passwords while defining network policies and procedures to enhance security and access control.
- Configured, maintained, and upgraded customer networks and in-house servers, ensuring reliable connectivity and system performance.
- Oversaw Linux system administration and configuration maintenance governing user access, privacy and data integrity.
- Designed endpoint management strategy for operation of various systems and devices.
- Orchestrated and oversaw upgrades to system hardware and software.
- Configured and updated Linux servers with the latest releases and patches.
- Performed patch, update, security scanning and configuration to meet OS performance mandates.
- Updated existing software and firmware immediately upon vendor release to mitigate risks.
- Managed thin client deployment and maintenance for user workstations. along with the servers used to maintain and provide server to military members at desks.
Education
Associate of Applied Science - Information Technology
Community College of the Air Force
Montgomery, AL06-2020
Bachelor of Science - Homeland Security
Middle Tennessee State University
Murfreesboro, TN05-2016
Skills
- Cisco routing
- VLAN configuration
- Switch configuration
- Firewall configuration
- Windows server administration
- Network diagnostics
- Network security
- Access control
- VLAN management
- IP addressing and subnetting
- Virtualization management
- VMware administration
- Windows server administration
- Linux system administration
- Active Directory
- Access control
- VLAN management
- Port security
- Attention to detail
- Cross-functional teamwork
- Communication skills
- IP addressing and subnetting
- Network security
- Communication skills
Certification
COMPTIA Security Plus Certification
Timeline
Network Engineer
Applied Research Solutions
05.2023 - Current
System Administrator
Air Force
12.2020 - 06.2022
Cyber Systems Operator
Air Force
12.2017 - 12.2020
Associate of Applied Science - Information Technology
Community College of the Air Force
Bachelor of Science - Homeland Security
Middle Tennessee State University