Infrastructure Engineer

O'Neill & Brennan; Potters Bar; On-site; GBP 40,000 - 60,000; Full time

Job summary

O'Neill and Brennan is seeking an Infrastructure Engineer to lead the IT Helpdesk and manage our Microsoft server, desktop, 365, and Azure environments. You will collaborate with Developers, Azure Architects, and Network Architects on infrastructure and cloud projects.

The role reports to the Head of IT Operations and requires strong customer service and 2+ years in IT infrastructure/support, with proficiency across AD, Entra ID, Defender, Intune, and PowerShell.

Qualifications

• Experience supporting Windows desktops and servers (minimum 2 years).
• Strong Microsoft 365/Azure cloud experience and IT service delivery.
• Customer-service focus with mentoring/leadership experience.

Responsibilities

• Lead and mentor the IT Helpdesk team ensuring timely ticket resolution.
• Manage and maintain Microsoft server, desktop, Azure, and 365 environments.
• Support and administer Active Directory and Entra ID with SSO/CA policies.

Skills

Active Directory management

Azure AD / Entra ID

PowerShell scripting

Azure backup & site recovery

Intune device management

Microsoft 365 administration

Endpoint protection (Defender)

SSO / Conditional Access

Desktop & server support

Project / ticketing familiarity

Tools

ServiceDesk Plus

Azure

Intune

Microsoft Purview

Microsoft Defender for Endpoint

Job description

The Position

The Infrastructure Engineer will provide effective IT and infrastructure support across all aspects of the business, locally and throughout all regional offices. The role is responsible for managing the IT Helpdesk team, ensuring calls and tickets are logged and resolved in a timely manner, while also taking ownership of the company's Microsoft Server, Desktop, Microsoft 365, Azure cloud, networking, and endpoint management environments. The role works closely with the Developers, Azure Architects, and Network Architects to support and evolve the organisation's infrastructure, and provides exposure to a wide range of infrastructure, networking, and cloud projects.

This role reports directly to the Head of IT Operations.

Duties / Areas of Responsibility

The position will involve the following areas of responsibility:

• Managing and mentoring the IT Helpdesk team, ensuring calls are answered and tickets are logged and resolved in a timely manner
• Diagnosing and resolving technical issues remotely and on site
• Undertaking small- to medium-sized IT and infrastructure projects as instructed by management
• Providing desktop and server support
• Supporting and maintaining Microsoft Server / Desktop operating systems, Microsoft 365, and Azure environments
• Setting up and configuring new laptops, desktops and mobile phones (Android and iOS)
• Installing and maintaining authorised software
• Reporting faults and maintaining logs on servers, desktops and laptops
• Completing internal user desk moves
• Ensuring all logs for equipment and users are maintained
• Making and logging purchases for IT equipment
• Ensuring licensing for all software purchased is recorded and maintained
• Active Directory, Microsoft Entra ID (Azure AD) and Microsoft 365 user maintenance, including Single Sign-On (SSO) and Conditional Access policy administration
• Responsible for managing Azure Backups / Recovery Services Vault configurations
• Managing disaster recovery and business continuity using Azure Site Recovery, including replication, failover, reprotect and failback of critical infrastructure
• Administering Microsoft Purview for data governance and compliance, and Microsoft Defender for endpoint and identity protection
• Managing endpoint devices via Microsoft Intune, including device enrollment, configuration and compliance policies
• Writing and maintaining PowerShell scripts to automate routine administrative and operational tasks
• Preparing documentation and user guides
• Performing basic administrative support duties, as required, to meet specific operational objectives
• Ensuring that a high level of customer service and support is provided to all internal and external staff
• Supporting custom internal applications
• Working alongside Developers, Azure Architects, and Network Architects on infrastructure and networking design and delivery

Skills and Experience

The ideal candidate will have a high level of customer service experience and Microsoft certifications. A minimum of 2 years of experience supporting Windows Desktops and Servers is required, along with all the expected qualities of an experienced Infrastructure / Support engineer.

Essential skills

• Active Directory management – Users and Computers, Group Policy, Network Printers, Shares, etc.
• Microsoft Entra ID (Azure AD), including SSO and Conditional Access configuration
• Microsoft Purview for data governance and compliance
• Microsoft Defender (endpoint and identity protection)
• Azure Site Recovery and Recovery Services Vault – replication, failover, reprotect, and failback
• PowerShell scripting for automation of administrative and operational tasks
• Windows 10 / 11 administration
• Windows Server administration, version 2016 to 2025
• Office 365 / Microsoft 365 user and mailbox administration

Cloud & infrastructure experience (Microsoft Azure)

• Azure Virtual Machine deployment, administration, and troubleshooting (boot diagnostics, serial console, run command, redeploy)
• Azure Virtual Desktop and FSLogix
• SQL Server administration on Azure VMs, including SSMS
• Exchange Hybrid configuration and troubleshooting
• Microsoft Teams voice administration, including Operator Connect

Networking

• General network administration and troubleshooting – TCP/IP and WAN / LAN / Wi-Fi
• Patching of network and phone cabling
• Azure Virtual Networks, subnets, VNet peering, and hub-and-spoke network design
• VPN Gateway configuration (Point-to-Site and Site-to-Site) and route troubleshooting
• Network Security Groups (NSGs) – inbound/outbound rule design and troubleshooting
• Knowledge of Cisco Unified Communications Manager (Cisco Unify / Cisco UC) – call routing, telephony administration, and troubleshooting
• Familiarity with switching, routing and Wi-Fi infrastructure in a business environment

Desirable skills

• Experience maintaining a helpdesk ticketing system (preferably ServiceDesk Plus)
• Incident Management skills, with the ability to identify root cause and apply solutions to resolve
• Problem Management skills, able to investigate trends and apply a methodical approach to identify root cause and possible solutions
• Proven experience working within IT service delivery
• Troubleshooting and problem-solving skills
• Ability to transfer knowledge within the team or to end users
• Experience with mobile device management (MDM) solutions (Meraki, SOTI)
• Microsoft Intune – device configuration profiles, compliance policies and app deployment
• Endpoint management across Windows, macOS, iOS and Android devices
• Device enrollment (Windows Autopilot, Apple Business Manager / Automated Device Enrollment, Android Enterprise zero-touch)
• Mobile Application Management (MAM) and app protection policies
• Microsoft Defender for Endpoint policy management via Intune

Good to know

• Barracuda email filtering

Team & Reporting Structure

The successful candidate will manage the IT Helpdesk team and work closely alongside the Developers, Azure Architects, and Network Architects.

O’Neill and Brennan values diversity and promotes equality, All individuals will be treated in a fair and equal manner and in accordance with the law regardless of gender, marital status, race, religion, colour, age, disability or sexual orientation