Infrastructure Engineer

Position: Infrastructure Engineer -
Infrastructure Engineer Rate: up to £530 per day (Umbrella only)

Clearance Required:

BPPS Duration: 6 months

Location:

Manchester or Inverness, 5 days onsite We are seeking an experienced Senior Identity Infrastructure Engineer to support and maintain the core identity infrastructure platforms that underpin the organisation's Identity and Access Management (IDAM) services. The successful candidate will be responsible for the administration, support, security, and continuous improvement of the Active Directory, PKI, DNS, Group Policy, and authentication infrastructure. They will work closely with the wider IDAM team, supporting critical identity services and providing L2/L3 operational support across the identity estate where required.

This role requires a highly capable infrastructure engineer with deep expertise in Microsoft Active Directory and Public Key Infrastructure (PKI), combined with a strong understanding of enterprise identity technologies and authentication services. The position is based within secure facilities in either Inverness or Manchester, working closely with security, engineering, and IDAM teams to ensure the availability, resilience, and security of critical identity platforms.

Key Responsibilities Administer and maintain enterprise Active Directory forests, domains, and domain controllers. Manage Active Directory Sites and Services, replication topology, trusts, and directory services infrastructure. Administer AD-integrated DNS and support authentication services across the enterprise. Manage and maintain Group Policy architecture, including policy design, implementation, troubleshooting, and lifecycle management. Support Active Directory backup, recovery, disaster recovery, and business continuity processes.

Monitor platform health, performance, security, and replication. Support Active Directory upgrades, migrations, consolidation projects, and infrastructure improvements. Implement and maintain Active Directory security hardening standards and privileged access controls. Public Key Infrastructure (PKI) Administer and support Microsoft Active Directory Certificate Services (AD CS). Manage Certificate Authorities, certificate templates, certificate enrolment, and certificate lifecycle processes. Support Offline Root CA and Issuing CA infrastructure.

Administer Certificate Revocation Lists (CRL), Authority Information Access (AIA), and certificate distribution services. Monitor certificate compliance, renewals, revocations, and expiration management. Maintain PKI operational documentation, recovery procedures, and security standards. Support cryptographic and certificate-related troubleshooting across infrastructure and security platforms. Identity Infrastructure & Authentication Services Support Microsoft Entra Connect and hybrid identity infrastructure. Maintain LDAP, LDAPS, Kerberos, and NTLM authentication services.

Support integrations between Active Directory and enterprise identity platforms including MIM, Entra , Okta, and Beyond Trust. Assist with identity-related service improvements and platform optimisation initiatives. Support authentication, directory, and identity infrastructure incidents through to resolution. Work collaboratively with the IDAM engineering team to support critical identity lifecycle services. IDAM Support Activities Provide L2/L3 support for identity-related incidents and service requests.

Assist with troubleshooting user provisioning, synchronisation, and authentication issues. Support MIM, Entra , Okta, and Beyond Trust integrations where infrastructure expertise is required. Collaborate with IDAM engineers to investigate root causes and implement long-term solutions. Support operational activities across the wider identity ecosystem during periods of increased demand. Automation & Continuous Improvement Develop and maintain Power Shell automation for identity infrastructure administration.

Drive service improvements, platform optimisation, and operational efficiencies. Contribute to security improvement initiatives, vulnerability remediation, and infrastructure modernisation. Produce and maintain technical documentation, operational procedures, and support runbooks. Essential Experience / Skills Extensive hands-on experience administering enterprise Active Directory environments. Strong knowledge of:
Active Directory Domain Services (AD DS) Active Directory Sites and Services Forest and Domain Administration DNS Group Policy LDAP / LDAPS Kerberos Authentication Trusts and Replication AD Backup and Recovery Experience troubleshooting complex authentication and directory service issues. PKI Strong experience administering Microsoft Active Directory Certificate Services (AD CS). Experience managing:
Certificate Authorities Certificate Templates CRL and AIA Infrastructure Certificate Lifecycle Management Certificate Enrolment Services Key Recovery and Archival Experience supporting enterprise PKI environments. Infrastructure Platforms Windows Server…