F5 Network Engineer

Core4ce is seeking a Senior Enterprise Network Services Engineer to design, implement, and maintain secure and scalable enterprise network infrastructures. The ideal candidate will have a strong background in network engineering, security, routing, firewall management, load balancing, and automation, and will be responsible for planning IT security projects, troubleshooting complex network issues, and ensuring compliance with security policies.

Responsibilities:

• Design, configure, install, and manage enterprise network infrastructure, including routers, switches, firewalls, and load balancers
• Plan and schedule the installation or modification of network hardware and software
• Implement and maintain secure network configurations across multi-VRF Cisco routers and enterprise environments
• Troubleshoot and analyze TCP/IP network traffic, including TCP 3-way handshake, TCP window scaling, and MSS
• Capture and analyze network packets using TCPDump (Linux) and Flow Monitor Capture (Cisco ASR)
• Implement multi-protocol routing solutions with BGP, OSPF, and VRF-based networks
• Use Wireshark, TCPDump, and other diagnostic tools for network performance analysis
• Perform TLS/SSL handshake troubleshooting and security configuration
• Configure and maintain firewalls (Palo Alto, Cisco), including security policies, VPNs, and intrusion prevention systems (IPS)
• Implement AAA technologies (Cisco ISE, LDAP, OTP) for access management
• Ensure certificate management and encryption, including TLS/SSL and OpenSSL operations
• Install, configure, and troubleshoot digital certificates on F5 LTM/GTM/APM/ASM appliances
• Implement F5 Client Constrained Delegation (C3D) for certificate delegation
• Enable certificate-based authentication using Client-SSL profiles and APM policies
• Deploy and maintain network monitoring, alerting, and repair systems in production environments
• Troubleshoot BGP neighbor configurations, VPNv4 unicast summary, and OSPF network participation
• Analyze DUP ACK packets, out-of-order segments, and retransmission issues
• Optimize and troubleshoot load balancing solutions and DNS-based traffic management
• Manage and support cloud-based network services across Azure, AWS, and Oracle Cloud
• Configure and maintain virtualized network appliances in VMware environments
• Utilize Python and BASH scripting for network automation and troubleshooting
• Develop scripts using REST APIs, Syslog, XML, and SNMP for automation
• Use regular expressions (e.g., ".*", "^", "$") for scripting and log parsing

Requirements:

• Minimum 4 years of hands-on experience as a Network Administrator or Network Security Engineer
• Secret clearance w/Tier 5 investigation
• Strong knowledge of OSI and TCP/IP network models, TCP 3-way handshake, and window scaling
• Experience with Palo Alto and Cisco firewalls
• Experience with F5 LTM, GTM, APM, ASM for load balancing and security
• Cisco Certified Network Professional (CCNP) certification or equivalent experience or willingness to get within 45 days of hire
• Strong troubleshooting skills with routing protocols (BGP, OSPF, VRF, LISP)
• Familiarity with network packet capture tools (TCPDump, Wireshark)
• Understanding of essential network services (DNS, SMTP, NTP, IMAP, SNMP)
• Experience in TLS/SSL security, OpenSSL, and certificate management
• Proficiency in scripting languages (Python, BASH) and automation tools
• Experience working with Unix/Linux-based systems
• Experience with network automation (REST APIs, Syslog, XML, SNMP)
• Experience deploying and troubleshooting load-balanced services and SSL certificate management
• Familiarity with multi-cloud networking (Azure, AWS, Oracle Cloud)
• Experience working with Puppet Labs or SaltStack configuration management