> Markdown version of [/jobs/ext/2283195-l3-engineer-server-firewalls-networking](https://www.wearedevelopers.com/jobs/ext/2283195-l3-engineer-server-firewalls-networking). Every page supports `.md` or `Accept: text/markdown`. Links point to the HTML versions so they work for humans too. Agent guide: [/agents.md](https://www.wearedevelopers.com/agents.md). --- # L3 Engineer (Server, Firewalls & Networking) - **Company:** Cornerstone Barricades - **Location:** United States (Remote available) - **Experience:** Experienced - **Contract:** Permanent contract - **Skills:** Microsoft Windows, Active Directory, Application Firewall, Microsoft Azure, Cloud Computing, CompTIA Network+, Dynamic Host Configuration Protocol, Domain Name System (DNS), Hyper-V, Issue Tracking Systems, Virtual Private Networks (VPN), Network Security, Network Troubleshooting, Windows Servers, Routing, Windows PowerShell, Azure Active Directory, Virtual Local Area Networks, Virtualization Technology, VMware VSphere, Wireless Networks, Computer Networking Systems, Cloud Platform System, Computer Network Technologies, Sonicwall, Fortinet, Vmware - **Published:** August 28, 2026 - **Apply:** https://uptimesolutions.betterteam.com/l3-engineer-(server-firewalls-networking)-1/apply ## About the Role * Strong communication skills and confidence dealing directly with clients and third-party vendors, providing clear and professional communication throughout the support process and challenging where appropriate. * At least 3 years' experience as a Server & Network Engineer or Level 3 Infrastructure Engineer, ideally within a Managed Service Provider or similar multi-client environment. * Experience monitoring, troubleshooting, and resolving complex server, virtualisation, networking, and security incidents, including possible out-of-hours work on a support rota. * Experience supporting project delivery into BAU, including server migrations, infrastructure upgrades, virtualisation projects, network refreshes, and cloud transitions. * Strong experience administering Windows Server environments, Active Directory, DNS, DHCP, Group Policy, Microsoft 365, Azure AD/Entra ID, and PowerShell. * Advanced experience deploying, administering, and troubleshooting virtualisation technologies including VMware vSphere and Microsoft Hyper-V. * Extensive networking experience including routing, switching, VLANs, VPNs, wireless networking, and network performance troubleshooting. * Expert-level firewall administration and security management, with specific experience supporting SonicWall and FortiGate environments. * Experience using a ticket management system (such as ConnectWise). Essential Criteria: * Microsoft Certifications such as AZ-104, Windows Server, Azure, or equivalent Microsoft infrastructure certifications. * Hands-on experience administering Microsoft 365 and Azure environments. * CompTIA Network+, Security+, or equivalent networking/security certification. * CCNA or equivalent networking certification. * Experience using a helpdesk/ticketing system (such as ConnectWise). * Product-related certifications or proven experience in VMware, Hyper-V, SonicWall, Fortinet, Azure, or similar technologies. * Experience owning and managing infrastructure services at a third-line level, including service improvements and proactive maintenance. * Strong understanding of core networking concepts including VLANs, DNS, DHCP, VPNs, routing protocols, switching, firewall management, and network security. * Knowledge of ITIL practices (or similar frameworks) and service management., * Strong problem-solving skills and a proactive mindset, with the ability to translate technical concepts for non-technical audiences. * A commitment to continuous learning and adaptability to stay updated with relevant infrastructure, networking, and security technologies. * Track record of mentoring and supporting colleagues to help develop a high-performing technical team. ## Description We are seeking a highly capable and customer-focused Server & Network Engineer to join our Service Team, providing effective remote and telephone-based technical support to our customers. You'll be a key escalation point for complex server, virtualisation, networking, and firewall-related issues, while also contributing to project deployments to ensure a smooth transition into BAU. You will play an important role in shaping and enhancing the service we deliver to clients, bringing strong technical expertise across server infrastructure, virtualisation platforms, networking, and security technologies. This is a hands-on role ideal for someone who thrives in a fast-paced, multi-client environment and is confident working across on-premises and cloud-based infrastructure. The successful candidate will have strong experience with Hyper-V and VMware, along with extensive knowledge of network security technologies, particularly SonicWall and FortiGate firewalls. A strong networking background is essential, including advanced understanding of routing, switching, VLANs, VPNs, and network troubleshooting. Your initiative will be crucial in supporting the Service Delivery Team and providing technical guidance to other engineers. This role is to support one of our UK Clients and the hours will be in line with UK working hours. 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