Senior Network Engineer

DayOne operates hyperscale data center campuses in Lahti and Kouvola and is continuing to expand its presence in Finland. As we scale our operations, we are strengthening our IT Infrastructure team to support reliable, secure, and high-performing network services across the organization. This position is based at our Helsinki office and serves both our corporate and data center environments. Occasional travel to our data center campuses in Lahti and Kouvola is expected as part of the role. As a Senior Network Engineer, you will be responsible for supporting, maintaining, and optimizing DayOne's network infrastructure across corporate and data center environments. You will ensure the availability, performance, and security of critical network services, while working closely with regional and global IT teams to deliver projects, resolve complex technical issues, and drive continuous improvements. Your key responsibilities will include, Network Architecture and Continuous Improvement Identifying gaps and deficiencies in current network architecture and operations. Proposing improvement plans and driving implementation activities. Supporting the evolution of network standards, documentation, and operational processes. Network Operations and Troubleshooting Troubleshooting and resolving complex network issues, including root cause analysis, performance tuning, and incident management. Managing routers, switches, firewalls, and wireless infrastructure, including configuration, maintenance, and security hardening. Monitoring network performance, identifying bottlenecks and single points of failure, and implementing improvements to enhance reliability. Network Design and Project Delivery Designing, implementing, and maintaining data center and workplace network environments. Collaborating with cross-functional teams to ensure successful project delivery and compliance with IT governance standards. Supporting capacity planning, scalability initiatives, and lifecycle management activities across Day 0, Day 1, and Day 2 operations. Automation and Monitoring Developing and maintaining automation scripts, configuration templates, and backup strategies. Managing network monitoring, alerting, and reporting platforms. Supporting operational visibility through monitoring tools and performance analytics. Security and Compliance Ensuring secure transmission of internal data and compliance with network security standards. Implementing and maintaining network security controls and best practices. Supporting ongoing initiatives to strengthen infrastructure resilience and security posture. Requirements Technical skills Minimum 5 years of experience in network engineering, implementation, and operations. Strong hands-on experience in enterprise and/or data center network environments. Proven ability to troubleshoot complex network issues and deliver end-to-end solutions. Experience in network design, planning, and project implementation. Experience working in global enterprise environments, large-scale infrastructure environments, or consulting organizations is considered an advantage. Network & Protocols Strong knowledge of IP routing and switching technologies, including OSPF, BGP, and MPLS VPN. Experience with SD-WAN technologies. Solid understanding of LAN and WAN architectures. Devices & Platforms Hands-on experience with Cisco, H3C, Aruba, and other enterprise networking platforms. Strong familiarity with routers, switches, firewalls, and wireless networking solutions. Security Experience with Fortinet firewalls, WAF solutions, NAC platforms such as ISE or FAC, and network security controls. Good understanding of network security monitoring and industry best practices. Tools & Automation Experience using network monitoring tools such as Zabbix, Grafana, and ELK. Familiarity with IPAM platforms, configuration management, backup solutions, and automation tools. Certifications CCNP, CCIE, or equivalent practical experience is considered highly beneficial. Soft skills Effective and clear communication skills with the ability to collaborate across technical and business teams. Strong analytical and problem-solving capabilities. Proactive, solutions-oriented mindset with high integrity and a collaborative working style. Ability to work in a fast-paced operational environment. Proficiency in English, both written and spoken. Knowledge of Finnish is considered a benefit. Why Join DayOne? Be a part of a company scaling fast in a booming industry. Work on an international stage with global leaders. Shape your career in a culture that values curiosity, agility, and bold thinking. If you're ready to grow with one of the fastest-moving companies in the data center industry, apply now and be part of our global journey. We are an Equal Opportunity Employer DayOne is an equal opportunity employer committed to building a diverse and inclusive workplace. We welcome applications from all qualified individuals regardless of race, ethnicity, gen