Senior IT Support Engineer (3rd line)

Senior IT Support Engineer (3rd Line Support)

Northampton (Hybrid)

Monday – Friday, full time permanent

Up to £42,000 DOE

We are seeking an experienced Senior IT Support Engineer with proven 3rd Line Support expertise to join our client's growing IT team. The successful candidate will be responsible for resolving complex technical issues, maintaining and improving IT infrastructure, supporting business-critical systems, and leading IT projects from initial planning through to successful implementation and handover.

This role requires strong troubleshooting skills across desktop, server, network, cloud, and security technologies, alongside in-depth knowledge of firewalls and network security. You will play a key role in delivering infrastructure projects, mentoring junior engineers, and driving continuous improvement across the IT estate.

Key Responsibilities:

• Provide 2nd and 3rd Line technical support for users across multiple sites.
• Investigate, troubleshoot, and resolve complex hardware, software, server, network, and infrastructure issues.
• Act as the primary technical escalation point for the Service Desk team.
• Administer and support Microsoft 365 services, Azure AD/Entra ID, Windows Server, Active Directory, DNS, DHCP, and Group Policy.
• Configure, maintain, and troubleshoot networking infrastructure including switches, routers, wireless solutions, VPNs, and enterprise firewalls.
• Take ownership of firewall administration, including security policies, NAT, VPN configuration, rule management, firmware updates, monitoring, and troubleshooting.
• Ensure network security best practices are maintained through firewall optimisation, vulnerability remediation, and access control management.
• Lead and deliver IT infrastructure projects from initial scoping and planning through implementation, testing, documentation, user handover, and post-project support.
• Work with internal stakeholders to gather technical requirements, produce implementation plans, and ensure projects are delivered on time and within scope.
• Perform system upgrades, patch management, software deployments, and infrastructure improvements.
• Monitor system performance and proactively identify opportunities to improve availability, reliability, and security.
• Maintain accurate technical documentation, knowledge base articles, network diagrams, and operational procedures.
• Support backup, disaster recovery, and business continuity solutions.
• Liaise with third-party vendors and managed service providers where required.
• Ensure compliance with IT security policies, industry best practices, and regulatory requirements.
• Mentor and provide technical guidance to junior IT engineers and Service Desk analysts.

Required Skills & Experience:

• Proven experience in a Senior 2nd Line or 3rd Line IT Support role within an enterprise environment.
• Strong experience supporting Microsoft technologies including Microsoft 365, Windows Server, Active Directory, Azure/Entra ID, Exchange Online, DNS, DHCP, and Group Policy.
• In-depth knowledge and hands-on experience managing enterprise firewalls (such as Sophos, Fortinet, Cisco, Palo Alto, WatchGuard, or SonicWall), including VPNs, NAT, security policies, and threat protection.
• Strong networking knowledge covering TCP/IP, VLANs, routing, switching, wireless networking, and network troubleshooting.
• Demonstrable experience delivering IT infrastructure projects from planning and design through implementation, testing, documentation, and completion.
• Experience working with virtualisation platforms such as VMware or Hyper-V.
• Knowledge of backup, disaster recovery, cybersecurity tools, and security best practices.
• Excellent troubleshooting, analytical, and problem-solving skills.
• Strong customer service, communication, and stakeholder management abilities.
• Ability to manage multiple priorities, work independently, and meet deadlines.
• Proactive, organised, and self-motivated with a continuous improvement mindset.
• Relevant IT qualifications or degree desirable.
• Microsoft certifications (Microsoft 365, Azure, Windows Server) and networking or firewall certifications (Fortinet NSE, Sophos, Cisco CCNA, etc.) are advantageous.