L3 Network Engineer (CISCO) - Must have an active SC Clearance
An opportunity is available for an experienced L3 Network Engineer (CISCO) to join a committed team supporting UK Military systems. This is a fully on-site role in Portsmouth and requires strong 3rd line network support expertise, particularly in secure environments. You will work on incident resolution and system change implementation across LAN and WAN networks.
Key Responsibilities
Provide 3rd line support for LAN and WAN environments
Manage escalated incidents from 1st and 2nd line teams
Implement approved changes to live systems
Install, configure, maintain and troubleshoot routers, switches, firewalls and related cabling infrastructure
Perform IOS and firmware upgrades on network devices
Update and maintain network design documentation
Offer network advice and input to design changes
Support operations in multi-security tier and multi-tenant environments
Mandatory Skills
Strong experience in 3rd line network support
Configuration and troubleshooting of CISCO devices
ASA and Firepower firewall experience
Familiarity with VMware NSX Firewall and SDWAN
Understanding of NGNIX and Linux systems
Experience in multi-tenant and high-security networks
Desirable Skills
Documentation of network changes and design updates
Effective collaboration with cross-functional teams
Experience supporting defence or military environments
This role is suited to an experienced and security-cleared network engineer who enjoys hands-on support in high-assurance environments.
