Sai Chandrika

Senior network and security engineer with 7+ years of experience designing, migrating and supporting enterprise LAN/WAN, data centers, multi-site SD-WAN, hybrid cloud and IT/OT infrastructure. Delivered a zero-downtime Cisco-to-Fortinet data-center migration, Palo Alto-to-FortiGate firewall cutovers and SD-WAN/ADVPN modernization across 10+ sites. Experienced in Cisco/Juniper architecture, Fortinet/Palo Alto security, AWS/Azure networking, VMware and Windows/Linux infrastructure, Python/Ansible automation, high availability and complex production troubleshooting.

IT Systems Engineer - Puffer-Sweiven LP - Houston, TX

(2025-07)

• Led a zero-downtime data-center network redesign and Cisco/Nexus-to-FortiGate/FortiSwitch migration, transitioning VLAN gateways, L3 routing, BGP, NAT, policies and application paths with staged cutovers and rollback plans.
• Modernized 10+ sites from Cisco/MPLS to Fortinet SD-WAN/ADVPN with BGP, dual ISPs, SLA-based steering and tested failover; migrated Palo Alto firewalls to FortiGate while validating NAT, VPNs and application access.
• Designed and documented reusable campus/branch architecture standards covering VLANs, IPAM, routing, management, WAN redundancy, device naming, wireless, monitoring, deployment and decommissioning.
• Supported 40+ Cisco Nexus/Catalyst, FortiSwitch, Aruba and Dell switches; resolved VLAN/trunk, STP, LACP, PoE, routing, uplink, SNMP and firmware issues while standardizing switch/AP deployment templates.
• Supported enterprise infrastructure and hybrid Azure networking (VNets, NSGs, VPNs), Windows Server/Active Directory, DNS/DHCP and virtual networking on VMware ESXi, KVM and Xen/XCP-ng, including host VLANs and firewall connectivity.
• Automated nightly FortiGate SFTP configuration backups using automation stitches; managed CAB changes, implementation and rollback plans, SOPs/MOPs, IPAM, Visio/Lucidchart diagrams and technical handoffs.
• Built and administered FortiGate, FortiSwitch, FortiAP, FortiNAC, FortiManager and FortiAnalyzer across data centers, offices, warehouses and subsidiaries; managed HA, IPS, segmentation, upgrades, logs, certificates and configuration backups.
• Built FortiNAC wired/wireless profiling and access policies; supported FortiClient certificate-based IPsec/EAP-TLS, Windows Always On VPN, NPS/RADIUS, AD/PKI, MFA and legacy SSL VPN migration; supported FortiSASE secure access.
• Operated Aruba, FortiAP, Cisco/Meraki and Ruckus wireless networks; troubleshot SSIDs, RF/signal, AP adoption, DHCP, authentication, VLAN assignments and corporate/guest/IoT connectivity.
• Troubleshot BGP peers, advertisements, next hops, asymmetric routing, SD-WAN selection, VPNs, NAT, DNS/DHCP, packet loss, firewall denies and application ports using FortiGate debug flow/sniffer, captures and Wireshark.
• Coordinated Lumen, Starlink and other ISP circuits, BGP handoffs, latency/bandwidth investigations and outages; validated WAN failover and secondary colocation/DR network paths and recovery connectivity.
• Monitored infrastructure through Zabbix/SNMP, FortiAnalyzer and Graylog; collaborated with Arctic Wolf on firewall assessments, log/traffic investigations and security remediation.
• Supported Emerson DeltaV IT/OT segmentation and application/server connectivity; troubleshot Citrix ADC/NetScaler, Cloudflare, DNS, NAT and backend paths for externally published applications.
• Designed and enforced DMZ and least-privilege segmentation across user, server, guest, management, vendor and IoT/OT zones; secured application publishing with NAT/VIPs, firewall policies, certificates and IPsec tunnels.
• Planned and tested primary-to-secondary data-center/colocation recovery paths, BGP/WAN failover, DR routing and application reachability; coordinated network dependencies for Zerto-based recovery with server teams.
• Worked with server and application teams on Windows Server, AD DS, NPS, DNS/DHCP, IIS and Linux connectivity, resolving certificate, authentication, .NET application and database traffic issues.

Network Security Engineer - Airbus - Remote

(2024-03 - 2025-06)

• Engineered global campus, WAN and data-center infrastructure across Cisco, Juniper, Aruba, Palo Alto and Check Point; designed and troubleshot BGP/OSPF/EIGRP, MPLS/VPLS, VRF, QoS, redistribution, multicast and resilient routing.
• Supported Nexus 9000 spine-leaf VXLAN/EVPN data-center fabrics and Catalyst 6500-to-Nexus 7000 modernization, including VLAN/VNI segmentation, Cisco ACI, switching redundancy and traffic-path analysis.
• Built and supported hybrid AWS/Azure/GCP network connectivity using AWS Direct Connect, VPC/VPN/NAT gateways, Route 53, Azure VNets/NSGs and GCP VPC; managed cloud firewall rules, DNS/IPAM and secure access.
• Automated Cisco/Juniper configuration backups, health checks and compliance validation using Python, Ansible, PowerShell and Terraform; analyzed device health, interface errors and performance with SolarWinds, Nagios and Wireshark.
• Administered Palo Alto NGFW (App-ID, User-ID, threat prevention, NAT, logging), Prisma Access and Prisma Cloud; supported Cisco ASA-to-Palo Alto migrations, translating policies, VPNs and security zones and validating application connectivity.
• Supported Juniper MX/M/T/J and SRX platforms (JUNOS, routing instances, filters, policy-options) and Cisco Nexus/Catalyst upgrades, incident escalations and vendor troubleshooting.
• Supported Cisco DNA Center/Software-Defined Access (SDA), Cisco ACI and campus upgrades involving Catalyst 6500/4500/3750/2960, Cisco Nexus, Meraki, voice QoS, access controls and segmentation.
• Deployed Meraki SD-WAN and supported Cisco Catalyst 9800 WLC, Meraki/Aruba wireless, 802.1X access, voice VLANs, DNS/DHCP and Active Directory services.
• Configured IPsec/SSL VPN, IDS/IPS and secure remote access; supported Zero Trust/ZTNA with Zscaler ZIA/ZPA and Prisma Access, identity-based access, RBAC/MFA, Entra integration and SOC/SIEM investigations.
• Configured F5 BIG-IP LTM/GTM and Citrix ADC/NetScaler virtual servers, VIPs, pools, nodes and SSL/application delivery; resolved backend routing and load-balancing failures.
• Supported enterprise change control, architecture reviews, SOC/security incident investigations, GDPR/HIPAA/PCI-related controls, SOPs/runbooks and junior engineer mentoring.
• Maintained IPAM and DNS integrations with Infoblox/AWS Route 53; assisted Windows Server/Active Directory, DHCP, Azure AD and MFA troubleshooting for enterprise network access.
• Worked with Cisco TAC and Juniper support on firmware upgrades, complex routing outages, packet loss and capacity issues; provided on-call production incident response.

Network Security Engineer - Trigyn Technologies - Hyderabad, India

(2019-05 - 2021-12)

• Administered Cisco ASA/PIX and Palo Alto firewalls, ACLs, NAT, IPS, VPN and Layer 4–7 security policies; supported Cisco Catalyst/Nexus, Aruba, Dell and Meraki network devices.
• Configured BGP, HSRP/VRRP/GLBP, VLAN/PVLAN, VTP, trunks, VSS, L2/L3 security and redundant WAN paths; troubleshot routing, switching and application access.
• Helped migrate branch circuits from TDM to MPLS and GRE/IPsec to Cisco GETVPN; supported Meraki SD-WAN and VPN connectivity for a 1,000+ user environment.
• Administered Cisco ISE access policies, upgrades and backups; resolved wireless, DHCP/DNS/WINS, IP conflicts, DMZ segmentation, VPN and firewall incidents within SLAs.
• Supported AWS/Azure/GCP VPC segmentation, firewall rules, IPAM/DNS and network change documentation; maintained Cisco IOS/TFTP configuration backups.
• Supported Cisco PIX/ASA 5500 and Catalyst 2960/3750/6500, implementing VLAN security, NAT/ACLs, DMZ firewall policies, IOS/TFTP backups and change validation.
• Supported enterprise network operations with structured incident triage, change validation, wireless troubleshooting, WAN performance analysis and escalation documentation.

Associate Network Engineer - M-Web Dev Pvt Ltd - Hyderabad, India

(2017-04 - 2018-05)

• Supported Cisco Catalyst 2960/3560, Cisco ASA and Juniper SRX firewalls, Juniper M320/T640 routing/filter policies, VLANs, NAT, VPN, ACLs and LAN/WAN troubleshooting.
• Assisted with T1/Metro Ethernet circuits, ISP coordination, routers/switches, fiber/Ethernet cabling, IP addressing and Wireshark/SNMP fault isolation.
• Created Microsoft Visio diagrams, configuration records, support documentation and troubleshooting procedures; supported security access controls and device deployments.
• Supported service-provider and enterprise circuit activations, switch/router installations, configuration backups, access controls and structured Ethernet/fiber infrastructure.

M.S. - Cybersecurity - Gannon University

B.Tech. - Electronics & Communication Engineering - Jawaharlal Nehru Technological University