L3 Network Security Engineer

Job Description – L3 Network Security Engineer (Infrastructure Specialist)
Role:
L3 Network Security Engineer

Department:
Cybersecurity / Infrastructure Security Operations

Location:
(Specify)

Experience:
5–10 Years

Type:
Full-Time

Role Overview
This role requires a
senior, infrastructure-heavy L3 Security Engineer
responsible for advanced operational management and troubleshooting of
network firewalls, IDS/IPS, WAF, proxies, and secure email gateways
. The engineer will act as the final technical escalation point for critical network security issues and play a key role in maintaining and optimizing the enterprise security infrastructure.

The ideal candidate must have deep hands-on experience with security appliances and tools, strong analytical skills, and the ability to support SOC teams with L3-level investigations.

Key Responsibilities

• L3 Operational Support
• Serve as the L3 escalation point for network security infrastructure issues.

• Handle advanced troubleshooting and deep-dive analysis for:

• Firewalls (rules, NAT, VPNs, routing issues)

• IDS/IPS (signature tuning, alert analysis)
• WAF (policies, false-positive reduction, rule adjustments)
• Proxy solutions (URL filtering, SSL interception, policy enforcement)

• Email gateways (anti-phishing, anti-spam, delivery issues)

• Perform system health checks, upgrades, patches, and configuration audits.

• Infrastructure Management

• Ensure the stability, performance, and security of the following systems:

• Enterprise firewalls

• IPS/IDS platforms
• WAF appliances or cloud-based WAF
• Proxy servers or cloud proxies

• Secure Email Gateways

• Monitor utilization, performance metrics, HA configurations, and redundancy.

• Policy & Configuration Management
• Review and optimize firewall, IPS, and proxy policies.
• Manage and evaluate change requests for infrastructure modifications.
• Apply best practices for access control, segmentation, and zero-trust implementation.
• Incident Response Support (L3)
• Support SOC teams by analyzing security events from infra devices.
• Participate in incident bridge calls for major security issues.
• Conduct root cause analysis (RCA) after incidents related to infrastructure components.
• Threat Detection & Tuning
• Tune firewall, IDS/IPS, WAF, and proxy rules to reduce false positives.
• Enhance detection coverage and strengthen security controls.
• Perform traffic analysis using logs, packet captures, and monitoring tools.
• Documentation & Reporting
• Maintain complete documentation of infrastructure components and configurations.
• Prepare operational reports, incident summaries, and RCA documents.
• Keep knowledge base updated for L1/L2 teams.

Required Technical Skills
Core Expertise (Mandatory)

• Strong hands-on experience with:

• Next-Gen Firewalls (Cisco ASA/FTD, Palo Alto, Check Point, Fortinet)

• IDS/IPS platforms (Firepower, Snort, Suricata, Palo Alto Threat Prevention)
• WAF solutions (F5 ASM, Imperva, Cloudflare/Akamai WAF)
• Proxy technologies (Blue Coat, Zscaler, Squid)

• Email Security Gateways (Cisco ESA, Proofpoint, Mimecast)

• Experience with routing, switching, IPSEC/SSL VPNs, DNS, DHCP.

• Proficiency with log analysis tools and packet capture (Wireshark, tcpdump).

Preferred Tools Experience
(Any combination is acceptable)

• FireEye appliances
• Cisco ASA/Firepower
• Cisco ISE
• Arbor DDoS
• AlgoSec/FireFlow

Soft Skills

• Strong problem-solving and analytical skills.
• Ability to handle high-severity incidents under pressure.
• Excellent communication with cross-functional teams.
• Good documentation and reporting skills.

Preferred Certifications

• CCNP Security / CCIE Security
• CISSP (added advantage)
• GIAC (GCIA, GCIH, GCFA)
• CEH / CHFI

Skills: infrastructure,waf,firewalls,skills,security,email,ids,proxy,network security,ips