Reby Jovanza Guestfint

[Cisco SF-300 / Python]

Developed a lightweight Flask-based web interface for remotely managing port access and device whitelisting on a Cisco SF300 switch over SSH.

Technical Highlights:

• SSH Automation: Used Python and Netmiko to remotely execute CLI commands and manage the switch.
• Port Access Control: Implemented 1-click port blocking and unblocking through the web interface.
• Whitelist Management: Added JSON-based device/port whitelisting with manual add, update, and delete functionality.
• Automatic Blocking: Automatically blocks active ports associated with devices not present in the whitelist.
• Port Monitoring: Retrieved and parsed switch interface status to display port type, speed, link state, and assigned device information.

[ESP-NOW / Hardware / Collaborative Project]

A collaborative project to develop a smart IoT safety ecosystem aimed at preventing kitchen fires. The system utilizes a dual-ESP32 architecture communicating wirelessly via the router-independent ESP-NOW protocol.

Technical Highlights:

• Gas Detection: Integrated an MQ-6 sensor for LPG detection and a speaker for local voice alerts.
• Emergency Shutdown: Engineered a motorized servo mechanism to physically trip the MCB switch, cutting house electricity during emergencies.
• Remote Notification: Integrated the CallMeBot API to send gas-leak alerts via WhatsApp.

My Contribution:

• Hardware & Integration: Primarily handled hardware assembly, soldering, and enclosure fabrication, with additional contributions to firmware development and overall system integration.

[RouterOS / VLAN / Layer 3 Firewall]

A hands-on network segmentation lab built with MikroTik RouterOS and a Cisco SF300 managed switch. The setup uses separate VLANs for main and lab environments, with dedicated DHCP services, Inter-VLAN routing, firewall isolation, and NAT for internet connectivity.

Technical Highlights:

• VLAN Segmentation: Configured VLAN 10 (192.168.10.0/24) and VLAN 20 (192.168.20.0/24) on MikroTik RouterOS to separate network environments.
• VLAN Trunking: Configured the Cisco SF300 uplink as a trunk carrying tagged VLAN 10 and VLAN 20 traffic from the MikroTik.
• Inter-VLAN Routing: Configured dedicated VLAN interfaces and gateways on MikroTik to enable Layer 3 communication between the segmented networks.
• DHCP: Configured separate DHCP services for each VLAN to automatically assign addresses to connected devices.
• Firewall Isolation: Implemented Layer 3 firewall filtering to prevent traffic from the lab VLAN from reaching the main network.
• NAT: Configured source NAT (masquerade) to provide internet access to the segmented VLANs.
• Traffic Monitoring: Used MikroTik's built-in graphing tools to monitor traffic across the VLAN interfaces.

[Python / Streamlit / Supabase / Flutter]

Developed a lightweight order management and shipping pipeline to streamline a real-world business workflow from quotation to delivery. The Streamlit web application manages product pricing and order data through Supabase, generates quotation, invoice, and delivery order documents, and creates QR-based shipping data for a companion Android label-printing application.

The Flutter companion app scans the generated QR code, automatically populates shipping and item details, and prints 80mm thermal labels with QR codes and Code 128 barcodes over Bluetooth.

Technical Highlights:

• Order & Document Management: Built a Streamlit-based workflow for creating quotations and generating invoices and delivery orders from stored order data.
• Cloud Database: Integrated Supabase to maintain the product catalog, pricing, order records, and document status.
• QR Data Pipeline: Generated compact JSON QR codes directly from delivery orders for transferring order data to the shipping app.
• Flutter Companion App: Developed an Android app to scan QR data, parse order details, and edit label information before printing.
• Thermal Printing: Integrated Bluetooth ESC/POS printing for QR codes, Code 128 barcodes, and customizable 80mm shipping labels.

[Linksys E900 / Python / Telegram API]

Designed and deployed a lightweight Telegram-based network management bot for a legacy Linksys E900 router, providing remote device monitoring and MAC filtering despite the router's lack of SSH-based management, overcoming stock firmware constraints without flashing custom ROMs.

Technical Highlights:

• HTTP Automation: Automated authenticated HTTP GET/POST requests to interact with the router's web management interface.
• DHCP Monitoring: Parsed the router's DHCP client table to retrieve connected device names, IP addresses, MAC addresses, and connection types.
• MAC Filtering: Implemented remote device blocking and bulk unblocking by programmatically updating the router's wireless MAC filter configuration.
• Telegram Interface: Built an interactive Telegram bot with inline controls for monitoring connected devices and blocking selected wireless clients.

[Cisco SF-300 / Python / InfluxDB / Grafana]

A personal networking project exploring SNMP-based telemetry by monitoring TX/RX traffic from a home Wi-Fi router connected to a Cisco SF300 switch.

Technical Highlights:

• SNMP Collection: Developed an asynchronous Python worker to periodically poll interface statistics from the Cisco SF300 via SNMP v2c.
• Data Processing: Calculated TX/RX bandwidth from interface counter changes between polling intervals.
• Time-Series Storage: Stored collected metrics in InfluxDB for historical analysis.
• Visualization: Built a Grafana dashboard with real-time gauges and historical traffic graphs.