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# 3rd Line Infrastructure Engineer - Windows

- **Company:** Modis
- **Location:** Hatfield, UK
- **Experience:** Expert
- **Salary:** £45,000.0 - £52,000.0
- **Contract:** Permanent contract
- **Skills:** Microsoft Windows, Active Directory, Active Directory Federation Services, Business Systems, Dynamic Host Configuration Protocol, System Center Configuration Manager, Windows Servers, Networking Basics, Routing, Public Key Infrastructure, Windows PowerShell, Azure Active Directory, Virtualization Technology, SSL Certificate Management, Firewalls (Computer Science), Vmware
- **Published:** October 24, 2026
- **Apply:** https://www.reed.co.uk/jobs/3rd-line-infrastructure-engineer-windows/57489162

## About the Role

You'll have demonstrable experience operating within large-scale enterprise infrastructure environments and possess strong troubleshooting and analytical skills.

Experience in several of the following technologies would be highly advantageous:

Active Directory, Group Policy, DNS & DHCP

Microsoft Windows Server

Azure AD / Entra ID, ADFS & SSO

VMware & Virtualisation Technologies

Exchange & Microsoft Collaboration Technologies

SCCM / Endpoint Management

PKI & Certificate Management

PowerShell Scripting & Automation

Infrastructure Monitoring & Security Tooling

Networking Fundamentals (LAN, WAN, Routing & Firewalls)

About You

 * Experienced in a 3rd Line Infrastructure or Senior Support role.
 * Comfortable working independently and solving complex technical challenges.
 * Strong communicator with a customer-focused approach.
 * Eligible to obtain Security Clearance (or already cleared).
 * Passionate about technology and continuous improvement.

## Description

We're partnering with a leading technology services organisation that supports some of the UK's most complex and secure IT environments. Due to continued growth, they're seeking a skilled Third Line Infrastructure Analyst to join a high-performing technical team supporting mission-critical services within a regulated enterprise environment.

This is an opportunity to work across a diverse infrastructure estate, combining advanced support, technical project delivery, and continuous improvement initiatives, all while collaborating with experienced engineers and technical specialists.

The Opportunity

As a senior member of the infrastructure support team, you'll take ownership of complex technical issues, contribute to key infrastructure projects, and help maintain the security, availability and performance of critical business systems.

You'll be trusted to investigate challenging incidents, implement infrastructure enhancements, and work closely with stakeholders to deliver reliable and secure technology services.

What You'll Be Doing

 * Providing expert 3rd Line support across enterprise-scale Windows environments.
 * Diagnosing and resolving complex infrastructure issues.
 * Designing, implementing and supporting Windows-based infrastructure solutions.
 * Supporting project delivery, upgrades and technical change activity.
 * Contributing to service improvement and infrastructure optimisation initiatives.
 * Producing and maintaining technical documentation.
 * Collaborating with customers, internal teams and technical stakeholders.
 * Participating in an on-call rota supporting critical services when required.