Firewall Engineer

Job Title: Firewall Engineer
Location: Sheffield
Salary/Rate: £420
Start Date: 27/05/2026
Job Type: 18-month contract inside IR35

Company Introduction

We have an exciting opportunity now available with one of our tier one banking clients! They are currently looking for a skilled Firewall Engineer to join their team for an 18 month contract.

We are seeking an experienced Firewall Engineer to join the Firewall Engineering team, responsible for designing, implementing, and supporting enterprise network security solutions. The role requires strong hands-on expertise with Fortinet and Juniper firewalls and the ability to operate at Level 3 (L3) support within a complex enterprise environment.

Key Responsibilities:

• Design, implement, and support Fortinet and Juniper firewall platforms.
• Provide L3 support for firewall-related incidents, problems, and complex service requests.
• Troubleshoot advanced network and security issues across enterprise environments.
• Manage firewall rulebases, NAT policies, security zones, and objects in line with security standards.
• Support firewall changes, upgrades, patching, and migrations.
• Perform root-cause analysis and drive permanent fixes for recurring issues.
• Collaborate with network, security, and infrastructure teams to ensure secure connectivity.
• Ensure compliance with internal security policies and regulatory requirements.
• Maintain accurate documentation, configurations, and operational procedures.
• Participate in on-call rotas and provide out-of-hours and weekend support when required to support business-critical services and incident resolution.

Required Skills/Experience

The ideal candidate will have the following:

• Minimum 5 years of hands-on experience in firewall engineering or network security roles.
• Strong expertise in Fortinet (FortiGate) and Juniper (SRX) technologies.
• Solid understanding of L3/L4 networking concepts, routing, and traffic flow.
• Proven experience providing L3 operational support in production environments.
• Strong troubleshooting and analytical skills.
• Ability to work effectively under pressure, including during major incidents.

Desirable:

• Experience working in regulated or enterprise environments (e.g. banking or financial services).
• Exposure to high-availability designs, VPN technologies, and security best practices.
• Relevant vendor certifications (e.g. Fortinet NSE, Juniper JNCIA/JNCIS).

If you are interested in this opportunity, please apply now with your updated CV in Microsoft Word/PDF format.

Disclaimer

Notwithstanding any guidelines given to level of experience sought, we will consider candidates from outside this range if they can demonstrate the necessary competencies.

Square One is acting as both an employment agency and an employment business, and is an equal opportunities recruitment business. Square One embraces diversity and will treat everyone equally. Please see our website for our full diversity statement.