Network Engineer

Circle B; Hoofddorp; On-site; EUR 70,000 - 110,000; Full time

Benefits offered by this job

Company gym

Modern office in Hoofddorp

Informal and open culture

Job summary

Circle B, based in Hoofddorp, NL, seeks a hands-on Network Engineer to own and operate our production network, including core routing, EVPN/VXLAN, and GPU cluster networking. You’ll work on a real ASN, datacenter networking, and drive changes that directly impact customers.

You will build out reliability, implement DDoS mitigation, and extend peering capabilities while maintaining IPv4/IPv6 addressing and subnet workflows. A strong security mindset and proactive documentation are essential.

Qualifications

• Proven experience operating production networks in hosting/datacenter/ISP-like environments.
• Strong practical knowledge of datacenter switching and L2/L3 fundamentals.
• IPv4/IPv6 operations and addressing design.
• Experience owning production changes: planning, validation, rollback thinking, and post-change checks.
• Fluent English (spoken and written).
• Strong hands-on network security experience (firewall policy, segmentation, change discipline, rule hygiene).
• Experience extending EVPN/VXLAN designs beyond day-to-day operations.
• Experience building DDoS mitigation workflows end-to-end.
• Experience driving improvements in low-structure environments.

Responsibilities

• Operate and improve our production network.
• Maintain and evolve our Juniper routing and switching environment.
• Own 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.
• Lead expansion into internet exchanges and peering: planning, implementation, validation, and turning it into a reliable operational capability.
• Implement routing-security best practices (e.g., RPKI/IRR hygiene and route-leak protections).
• Lead the implementation of a practical DDoS mitigation approach (technology + processes + runbooks).
• Documentation, observability, and operational quality: use NetBox, improve monitoring/alerting, and create/update diagrams and runbooks.
• Be helpful beyond networking when needed: support adjacent infra areas as priorities shift.

Skills

BGP

Juniper

EVPN/VXLAN

IPv4/IPv6

Network security

DDoS mitigation

RDMA/RoCE

GPU cluster networking

Production networking

Cloud/data center networking

Tools

NetBox

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
• Own 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

Build and mature capabilities

• Lead expansion into internet exchanges and peering: planning, implementation, validation, and turning it into a reliable operational capability
• Implement routing-security best practices (e.g., RPKI/IRR hygiene and route-leak protections)
• Lead the implementation of a practical DDoS mitigation approach (technology + processes + runbooks)

Documentation, observability, and operational quality

• Use NetBox as the source of truth for network inventory and IP addressing
• Improve monitoring/alerting and visibility (telemetry/logging/traffic insight) using the existing toolchain and extending it where needed
• Create and maintain diagrams, runbooks, and change documentation so the environment becomes easier to run over time

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 experience operating production networks in a hosting/datacenter/ISP-like environment
• Strong practical knowledge of:
• Datacenter switching and L2/L3 fundamentals
• IPv4/IPv6 operations and addressing design
• Comfortable owning production changes: planning, validation, rollback thinking, and post-change checks
• Fluent English (spoken and written)
• Strong hands-on network security experience (firewall policy, segmentation, change discipline, rule hygiene)
• Experience extending EVPN/VXLAN designs beyond day-to-day operations
• Experience building DDoS mitigation workflows end-to-end
• Experience driving improvements in environments with low structure (you bring structure without bureaucracy)
• Experience with GPU cluster networking; RDMA/RoCE in production

The working style that succeeds here

• You stay effective when priorities shift and interruptions happen
• You communicate clearly during incidents and changes
• You take ownership and enjoy making systems more reliable, more visible, 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.