Principal Network Engineer

Principal Network Engineer

Mimecast's Infrastructure & Operations/IT team is looking for a Principal Network Engineer to own the day-to-day operation, troubleshooting, and continuous improvement of our global corporate network. This role is based in Lexington, MA on a hybrid schedule, with a minimum of two days per week in the office, and reports to the Senior Director, IT Infrastructure. You'll work hands-on across Cisco, Juniper, and Aruba platforms, partnering closely with IT, Security, and Workspace teams to resolve complex issues, drive strategic upgrades, and use automation to raise operational efficiency worldwide. You'll help deliver the reliable, secure, high-performance connectivity that keeps every Mimecaster — wherever they work — seamlessly connected.

What You'll Do

• Own the design, build, and maintenance of network infrastructure across Mimecast's global office locations — including edge routing, enterprise switching, wireless, and out-of-band management — to support a hybrid workforce.
• Monitor, troubleshoot, and resolve complex issues across LAN, WAN, SD-WAN, SASE, and wireless services, ensuring optimal performance and minimal downtime for on-site and remote users.
• Partner with Security to implement and maintain network security policies, access controls, and segmentation strategies that protect corporate assets and user data.
• Partner with Workspace and IT teams to ensure network infrastructure seamlessly supports collaboration platforms, productivity tools, and hybrid work technologies.
• Own comprehensive network documentation, including topology diagrams, configuration standards, runbooks, and change management procedures.
• Lead network upgrade projects and technology refresh initiatives, evaluating new solutions and driving strategic improvements to performance and scalability.
• Leverage automation and scripting to streamline network operations, reduce manual effort, and improve configuration consistency across multi-vendor environments.
• Engage with business stakeholders and end users to understand evolving needs and continuously enhance the digital user experience.

What You'll Bring

• Demonstrated mastery of enterprise network engineering, with a track record independently designing, implementing, and supporting large-scale, multi-site network infrastructure with minimal oversight.
• Extensive hands-on expertise with Juniper platforms — including Mist, EX switches, and SRX firewalls — spanning configuration, troubleshooting, and optimization.
• Strong proficiency with Cisco Meraki solutions for cloud-managed switching, wireless, and security appliances.
• Proven ability deploying and managing Aruba wireless infrastructure across enterprise environments with multiple sites and diverse user populations.
• Working knowledge of Opengear or similar out-of-band management platforms for remote device access and network recovery.
• Experience with SASE and ZTNA solutions supporting secure hybrid cloud and remote workforce connectivity.
• Comprehensive enterprise wireless planning expertise, including RF site surveys, heat mapping, interference analysis, capacity optimization, and evolving Wi-Fi 6/6E/7 standards.
• Solid command of core network protocols — BGP, OSPF, spanning tree, VLANs, VPN technologies, and QoS.
• Skilled in network automation and scripting (Python, Ansible, or similar) to streamline operations and ensure configuration consistency.
• Bachelor's degree in Computer Science, Information Technology, or a related field, or equivalent practical experience; CCNP, CCIE, JNCP, or similar certifications preferred.
• Exceptional communication, interpersonal, and cross-functional collaboration skills, with a focus on delivering an outstanding user experience.

The base salary range for this position is 144,000 – 216,000 USD plus benefits. This range represents the minimum and maximum new hire compensation for this role. The position may also be eligible for incentive plans and additional benefits, in accordance with company policy and local regulations. Our salary ranges are determined by role, level, and location with individual compensation also dependent on factors such as qualifications, experience, and skills. Final offers will reflect these considerations and may vary accordingly.

Belonging at Mimecast

Cybersecurity is a community effort. That's why we're committed to building an inclusive, diverse community that celebrates and welcomes everyone – unless they're a cybercriminal, of course.

We're proud to be an Equal Opportunity and Affirmative Action Employer, and we'd encourage you to join us whatever your background. We particularly welcome applicants from traditionally underrepresented groups.

We consider everyone equally: your race, age, religion, sexual orientation, gender identity, ability, marital status, nationality, or any other protected characteristic won't affect your application.

If you require any adjustments or accommodations due to a disability, or any other reason that may help you in your interview process, please let us know by emailing View email address on click.appcast.io.

Due to certain obligations to our customers, an offer of employment will be subject to your successful completion of applicable background checks, conducted in accordance with local law.

It is unlawful in Massachusetts to require or administer a lie detector test as a condition of employment or continued employment.