Senior Network Security Engineer - Telecom at Ascentech Services Limited

Job Summary:

• We are looking for an experienced and highly skilled Senior Network Security Engineer to join our IP Backbone team in Lagos.
• The ideal candidate will have extensive experience (7+ years) securing large-scale network infrastructures and managing advanced security appliances.
• This role requires deep knowledge of next-generation firewalls (Cisco Firepower, Sophos XGS), VPN, SD-WAN, CGNAT, and L3 protocols, along with excellent troubleshooting and operational support skills.

Key Responsibilities:

• Design, implement, and maintain advanced network security solutions across ISP/Telecom infrastructure.
• Configure and manage Next-Gen Firewalls such as Cisco Firepower and Sophos XGS.
• Deploy and manage VPN solutions (IPSec, SSL), SD-WAN appliances, and remote access technologies.
• Administer and optimize CGNAT systems to support large-scale NAT deployments.
• Monitor and secure L3 protocols (OSPF, BGP) within backbone and customer-facing networks.
• Conduct threat analysis, risk assessments, and vulnerability mitigation.
• Lead incident response and forensic investigations for security breaches or outages.
• Collaborate with NOC, SOC, and infrastructure teams to ensure secure, stable, and highperforming network services.
• Maintain and update security documentation, configurations, and procedures.
• Provide off-hours and on-call support as required to ensure 24/7 network security coverage.

Requirements:

• 7+ years of hands-on experience in network security engineering, preferably in an ISP or telecom environment.
• Deep expertise in managing and troubleshooting Next-Gen Firewalls (Cisco Firepower, Sophos XGS, or similar).
• Experience with DDOS protection, anti-malware, and sandboxing tools and other NG-IPS Solutions and its deployment and optimization methods
• Strong working knowledge of VPN technologies, SD-WAN, and CGNAT solutions.
• Advanced understanding of Layer 3 protocols (OSPF, BGP) & Technologies usch as Route-map, Access-list, VRF.
• Proficiency with network security monitoring and log analysis tools (SIEM, IDS/IPS, etc.).
• Strong problem-solving and troubleshooting skills under pressure.
• Relevant certifications such as CCNP Security, Sophos Certified Engineer, or equivalent (strongly preferred).
• Excellent communication and documentation skills.
• Must be based in or willing to relocate to Lagos, Nigeria.
• Experience with automation tools (Python, Ansible) for security operations.
• Familiarity with compliance frameworks (ISO 27001, NIST, etc.).