Senior Network Security Engineer at Ascentech Services Limited

Ascentech Services Limited is a full-fledged Human Resource Solution Provider incorporated in 2013 with its Head Office in Lagos, Nigeria. We are committed to forging long-term partnerships with our clients by creating and delivering robust and flexible services that address the changing needs of their business.

We are recruiting to fill the position below:

Job Title: Senior Network Security Engineer

Location: Ikeja, Lagos
Employment Type: Full-time
Work Schedule: Full-Time | On-Call & Off-Hours Availability Required
Industry: ISP / Telecommunications

Job Summary

• We are seeking an experienced and highly skilled Senior Network Security Engineer to join our IP Backbone team in Lagos.
• This role is critical to maintaining the integrity, confidentiality, and availability of our large-scale ISP infrastructure.
• The ideal candidate will possess over 7 years of hands-on experience in network security engineering within an ISP or telecommunications environment, with strong expertise in next-generation firewalls, VPNs, SD-WAN, CGNAT, and Layer 3 routing protocols.

Key Responsibilities

• Design, implement, and maintain robust network security solutions across ISP/telecom infrastructure.
• Configure and manage Cisco Firepower and Sophos XGS Next-Gen Firewalls.
• Deploy and support VPN solutions (IPSec, SSL), SD-WAN, and remote access technologies.
• Administer and optimize CGNAT systems for large-scale NAT deployments.
• Secure and monitor OSPF, BGP, and other Layer 3 routing protocols within core and edge networks.
• Perform threat analysis, risk assessments, and mitigate vulnerabilities proactively.
• Lead incident response, forensic investigations, and post-mortem analysis for security events.
• Collaborate with NOC, SOC, and Infrastructure Teams to ensure secure and high-performing network operations.
• Maintain comprehensive and up-to-date security documentation and configurations.
• Provide on-call and off-hours support as needed to ensure 24/7 network security coverage.

Requirements

• Candidates should possess relevant qualifications in a related field.
• 7+ years of experience in network security engineering, preferably in an ISP or telecom environment.
• Proven expertise in managing Next-Gen Firewalls (Cisco Firepower, Sophos XGS, or equivalent).
• Experience with DDoS protection, anti-malware, sandboxing, and NG-IPS solutions.
• Proficiency in VPN technologies, SD-WAN, and CGNAT solutions.
• Advanced understanding of Layer 3 protocols (OSPF, BGP), route-maps, access lists, and VRFs.
• Skilled in using SIEM, IDS/IPS, and other network security monitoring/log analysis tools.
• Strong analytical and troubleshooting abilities under high-pressure situations.
• Relevant certifications such as CCNP Security, Sophos Certified Engineer, or equivalent (preferred).
• Proficient in Python, Ansible, or other automation tools used in security operations.
• Familiarity with compliance frameworks like ISO 27001 and NIST.
• Excellent verbal, written, and documentation skills.
• Must be based in or willing to relocate to Lagos, Nigeria.

Salary
N500,000 / Month (Negotiable).

Application Closing Date
Not Specified.

How to Apply
Interested and qualified candidates should send their CV to: cv@ascentech.com.ng using "Senior Network Security Engineer" as the subject of the email.