Senior Network & Systems Administrator

Job Summary:

Role Purpose:

Manage, maintain and optimise the organisation's network and systems infrastructure across on-premises, virtualised and cloud environments, ensuring the reliability, availability, security and performance of business-critical systems.

Lead and deliver infrastructure improvements, upgrades, migrations, hardware refreshes and disaster recovery activities, ensuring technology services remain resilient, efficient and fit for business needs.

Provide expert technical support and incident resolution across multiple sites, working collaboratively with UK and US teams and stakeholders to maintain operational continuity and drive ongoing improvements to the technology estate.

Job Description:

As a Senior Network & Systems Administrator , you will be responsible for the day-to-day management, optimisation, and support of our network and systems estate. You’ll work across on-premises and cloud environments, supporting business-critical systems, managing incidents, and delivering projects that drive our technology forward. This role is based in the UK and may require occasional out-of-hours support and collaboration with remote teams along with travel to our datacenters.

Key Responsibilities Include:

• • Patch and maintain systems (Windows, SQL, Citrix, .NET, etc.) to ensure reliability and performance.
  • Respond to infrastructure incidents and service requests using tools such as FreshDesk.
  • Plan and execute infrastructure upgrades, hardware refreshes, and customer migrations.
  • Monitor systems and networks using ManageEngine, Zabbix and Uptrends, including creating custom checks and responding to alerts.
  • Manage old Hyper-V environments (320+ VMs), Veeam and SQL offsite backups, and disaster recovery tests.

Manage new VMWare environment, Dell footprint

• • Oversee network operations including firewall management, DNS, domain routing, VPNs, and network support across multiple offices.
  • Administer IIS, file servers, Citrix, and support QA, Dev, UAT, and Production environments.
  • Plan, document, and implement change requests; maintain accurate records for compliance and operational continuity.
  • Provide ad-hoc technical support to colleagues, participate in meetings, and support business-as-usual operations.
  • Collaborate with the Security Engineer and other teams as needed, but primary focus is on network and systems.
  • Work closely with U.S. teams to support global infrastructure and planning

Essential Skills & Experience

• • Proven experience in network and systems administration, ideally in a multi-site or hybrid environment.
  • Strong knowledge of Windows Server, SQL, Citrix, VMWare, Hyper-V, networking (routing, VLANs, firewalls, SonicWall, FortiGate), and backup technologies.
  • Familiarity with monitoring tools (ManageEngine, Zabbix, Uptrends), ticketing systems (FreshDesk), and change management.
  • Ability to manage complex migrations, upgrades, and hardware refresh projects.
  • Excellent troubleshooting, documentation, and communication skills.
  • participate in out-of-hours support and occasional weekend work.

Worker Type:

Regular

Number of Openings Available:

1

About Trellint