Network Security Engineer

This critical role involves managing and maintaining the large-scale security infrastructure responsible for terminating Gi interface traffic originating from the mobile core network, primarily using Juniper SRX firewalls. You will ensure the security posture, availability, and performance of these firewalls, handling incident response, policy management, change implementation, and performance tuning. A solid understanding of mobile core network principles (GSM/GPRS/LTE) and relevant data flows is essential for effective troubleshooting in this demanding service provider context.

Key Responsibilities:

• Service Assurance: Monitor firewall health, performance (CPU, memory, session count), and traffic logs. Lead the response to security incidents or outages affecting Gi firewall services. Conduct thorough root cause analyses (RCAs) for security-related events and implement corrective/preventive measures. Develop and maintain SOPs and PMRs specific to firewall operations.
• Change Management: Implement, validate, and document firewall policy changes, software upgrades, hardware replacements/additions, and configuration modifications according to strict ITIL change management protocols. Assess the security impact of proposed changes.
• Performance Management: Utilize performance monitoring tools to track firewall throughput, session establishment rates, latency, and resource utilization. Analyze performance data to identify potential bottlenecks or required tuning. Optimize firewall configurations and policies for performance. Generate regular performance and security reports.
• Security Policy & Configuration Management: Implement, review, and audit firewall rulesets and security policies. Ensure configurations align with security best practices and customer requirements. Manage features like NAT (including CGNAT if applicable on the platform), Intrusion Prevention Systems (IPS), and Application Security.
• Problem Management: Proactively identify potential vulnerabilities or recurring issues based on log analysis, incident trends, and performance data. Drive complex problem resolution involving firewall infrastructure.
• Technical Leadership & Communication: Serve as a subject matter expert for Gi firewall infrastructure. Lead technical bridges during security incidents. Clearly communicate security risks, operational status, and technical details to management, other teams, and customers.
• Automation Awareness: Identify opportunities for automating repetitive security tasks (e.g., policy checks, log analysis snippets) using basic Python skills.

Required Qualifications & Experience:

• University Degree: Bachelor's degree in Computer Science, Information Security, Network Engineering, or a related field.
• Juniper Security Expertise: Minimum 5 years of hands-on experience operating, troubleshooting, and managing Juniper Networks SRX Series firewalls in a high-throughput, large-scale environment (preferably Service Provider or large enterprise).
• Security Concepts: Deep understanding of firewalling principles, stateful inspection, NAT/CGNAT, VPNs (IPSec), IPS/IDS, application security, and common network attack vectors.
• Networking Protocols: Strong knowledge of TCP/IP, routing protocols (BGP, OSPF/ISIS), and common application layer protocols (HTTP, DNS, etc.).
• ITIL Certification: ITIL Foundation certification is a plus.
• Python Scripting: Basic understanding and ability to read/write simple Python scripts for security or network tasks.
• Language: Fluency in English (written and verbal).

Desired Skills:

• Juniper Security Certifications (JNCIE-SEC).
• Mobile Network Knowledge: Understanding of GSM/GPRS/UMTS/LTE network architecture, key interfaces (Gi, Gn, SGi, etc.), and associated call/data flows is strongly desired to facilitate effective troubleshooting of issues related to mobile subscriber data traffic traversing the Gi firewall.
• Experience with CGNAT implementation and management.
• Experience in managed security services (MSSP) or telecom security.
• Strong analytical and critical thinking skills.
• Excellent communication skills, particularly in conveying security risks and operational status.