Senior Identity Infrastructure Engineer – Active Directory & PKI
Location: Manchester or Inverness, within secure facilities
About the role
We are seeking an experienced Senior Identity Infrastructure Engineer to support and maintain the platforms underpinning enterprise Identity and Access Management (IDAM) services.
You will administer, secure and improve Active Directory, Public Key Infrastructure (PKI), DNS, Group Policy and authentication infrastructure. Working closely with security, engineering and IDAM teams, you will provide L2/L3 operational support and help ensure critical identity platforms remain available, resilient and secure.
Key responsibilities
Active Directory infrastructure
• Administer enterprise AD forests, domains and domain controllers.
• Manage AD Sites and Services, replication topology, trusts and directory infrastructure.
• Administer AD-integrated DNS and Group Policy, including design, implementation, troubleshooting and lifecycle management.
• Monitor platform health, performance, security and replication.
• Support AD backup, recovery, disaster recovery and business continuity.
• Support upgrades, migrations, consolidation and infrastructure improvements.
• Implement security hardening and privileged access controls.
Public Key Infrastructure
• Administer Microsoft Active Directory Certificate Services (AD CS).
• Manage Certificate Authorities, certificate templates, enrolment and lifecycle processes.
• Support Offline Root CA and Issuing CA infrastructure.
• Maintain Certificate Revocation Lists (CRL), Authority Information Access (AIA) and certificate distribution services.
• Monitor certificate compliance, renewals, revocations and expiry.
• Maintain PKI documentation, recovery procedures and security standards.
• Troubleshoot cryptographic and certificate-related issues.
Identity infrastructure and operational support
• Support Microsoft Entra Connect and hybrid identity infrastructure.
• Maintain LDAP, LDAPS, Kerberos and NTLM authentication services.
• Support AD integrations with Microsoft Identity Manager (MIM), Entra ID, Okta and BeyondTrust.
• Provide L2/L3 support for identity incidents and service requests.
• Troubleshoot provisioning, synchronisation, authentication ...
Infrastructure Engineer employer: Cerco Careers
Cerco is an excellent employer for those looking to kickstart their IT careers, offering full training and support to ensure you thrive in the field. With a strong focus on employee growth and development, our collaborative work culture fosters enthusiasm and learning, making it an ideal environment for entry-level engineers. Located in Crewe, we provide unique opportunities to work with major UK businesses, ensuring that every team member is equipped with the skills and confidence needed for success.
