Network Engineer

Circle B; Hoofddorp; On-site; EUR 70,000 - 100,000; Full time

Benefits offered by this job

Company gym

Modern office in Hoofddorp

Informal and open culture

Conference participation across Europe

Skill development opportunities

Job summary

Circle B in Hoofddorp is seeking a hands-on Network Engineer to operate and expand our production network across multi-tenant hosting and datacenter environments. You will own core connectivity, manage BGP, EVPN-VXLAN, IPv4/IPv6 addressing, and work closely with platform engineering to implement secure, scalable networking for our GPU cloud and AI workloads.

This role requires practical design sense, strong troubleshooting skills, and a proactive attitude toward reliability, security, and

Qualifications

• Hands-on experience operating production networks in multi-tenant hosting, datacenter, or cloud environments.
• Strong knowledge of datacenter switching, L2/L3 fundamentals, and routing.
• Experience with EVPN/VXLAN, firewall policies, and security design.
• Ability to translate requirements into practical network designs and plans.
• Comfort with production changes, change management, validation, and rollback.

Responsibilities

• Operate and improve production network including Juniper routing/switching.
• Manage BGP on our ASN, including policy, filtering, communities, and traffic engineering.
• Implement EVPN/VXLAN in production and extend as we grow.
• Handle IPv4/IPv6 addressing and subnet allocation workflows.
• Translate customer requirements into multi-tenant network designs and plans.
• Design and implement peering and IX connectivity.
• Apply routing-security best practices and DDoS mitigation with guidance.
• Perform security assessments and implement network security improvements.
• Maintain NetBox inventory, improve monitoring, and document changes.

Skills

Production network operations

Datacenter networking

BGP management

EVPN/VXLAN

IPv4/IPv6 addressing

Network security

Firewall configuration

Network design

Incident communication

Documentation

Peerings and IX connectivity

Tools

Palo Alto firewalls

Juniper routing/switching

EVPN/VXLAN tooling

Job description

Circle B builds sustainable IT infrastructure for the AI and cloud era. For over a decade— we have designed and deployed datacenter, edge, and AI/HPC systems on Open Compute Project (OCP) hardware. We are independent, vendor-neutral, and ISO 9001 / 14001 / 27001 certified, with deployments across multiple countries.

Our newest initiative is a sovereign EU GPU cloud — operating under full Dutch/EU jurisdiction and beyond the reach of the US CLOUD Act, for regulated European organizations that cannot compromise on where their data lives.

The Role

Network Engineer — BGP / Juniper / EVPN-VXLAN / GPU Cluster Networking

The opportunity

We run our own hosting infrastructure and production network, and we’re looking for a hands-on Network Engineer who enjoys real ownership: operating core connectivity, improving reliability, and building out capabilities that directly matter to customers.

You’ll work on an environment with real routing (own ASN), real datacenter networking, and meaningful change-impact. If you like being close to the technology and seeing your work show up in production immediately, you’ll fit well.

What you'll do

Operate and improve our production network

• Maintain and evolve our Juniper routing and switching environment.
• Manage BGP operations on our ASN: routing policy, filtering, communities, troubleshooting, and traffic engineering.
• Operate EVPN/VXLAN in production and help extend it as we grow.
• Manage IPv4/IPv6 addressing and clean subnet allocation/assignment workflows.

Design and expand network capabilities

• Independently translate customer requirements into practical network designs for our multi-tenant hosting environment, including addressing, VLAN/VXLAN segmentation, routing, firewalling, redundancy, and implementation planning, with senior design review available for more complex solutions.
• Help design and implement our expansion into internet exchanges and peering, including planning, implementation, validation, and ongoing operations.
• Implement routing-security best practices (e.g., RPKI/IRR hygiene and route-leak protections).

Network security

• Perform security assessments of our existing network infrastructure, identifying vulnerabilities, architectural weaknesses, and opportunities for improvement.
• Design and implement practical security improvements, including network segmentation, firewall policies, access controls, and protection of management infrastructure.
• Maintain and improve our firewall environment, including policy management, rule hygiene, and secure customer isolation.
• Help develop and implement network security measures, including DDoS mitigation, in collaboration with our external senior network consultant when needed.

Documentation, monitoring, and operational quality

• Use NetBox as the source of truth for network inventory and IP addressing.
• Improve monitoring, alerting, and network visibility, including telemetry, logging, and traffic analysis, using the existing toolchain and extending it where needed.
• Create and maintain diagrams, runbooks, and change documentation to improve operational reliability.

Be helpful beyond networking when needed

When network workload is lighter, support adjacent infrastructure areas (Linux, virtualization, storage, automation, or occasional customer escalations) depending on your strengths and team priorities.

What we're looking for

Core requirements

• Proven hands-on experience operating production networks, preferably in a multi-tenant hosting, datacenter, ISP, cloud, or service-provider environment.
• Strong practical knowledge of:
• Datacenter switching and L2/L3 fundamentals.
• IPv4/IPv6 operations and addressing design.
• Practical knowledge of EVPN/VXLAN, preferably with hands-on production experience.
• Hands-on experience with network security, including firewall configuration and policy management, network segmentation, and secure network design. Ability to identify security weaknesses and implement appropriate improvements.
• Ability to independently translate technical requirements into practical network designs and implementation plans.
• Comfortable taking responsibility for production changes, including planning, validation, rollback procedures, and post-change checks.
• Fluent English (spoken and written).
• Hands-on experience with Palo Alto firewalls.
• Experience with internet exchange connectivity, peering, and routing security.
• Experience building DDoS mitigation workflows end-to-end.
• Experience driving improvements in environments with low structure (you bring structure without bureaucracy).

Additional opportunities

As Circle B expands its AI infrastructure, there may also be opportunities to contribute to GPU cluster networking. Experience with technologies such as RDMA/RoCE would be beneficial in this context, but is not expected for this position.

The working style that succeeds here

• You take ownership while recognizing when to involve others for guidance or design reviews.
• You stay effective when priorities shift and interruptions happen.
• You communicate clearly during incidents and changes.
• You enjoy making systems more reliable, more visible, more secure, and better documented over time.

Working model

This is an on-site role in Hoofddorp, 5 days per week, to stay close to the hardware, platform engineering, and execution environment.

• Company gym.
• Modern office in Hoofddorp.
• Informal and open working culture.
• Participation in relevant conferences and exhibitions across Europe.
• Opportunity to develop your skills in a fast-growing technology environment.

Our Work Culture

Circle B offers an informal working atmosphere with energetic people who enjoy being part of a growing technology company. We have an open management culture and encourage colleagues to contribute to improving our products, services, and processes.