DHCP Server Health Checks on macOS with dhcping
Manny Fernandez1. Title & Executive Summary Objective dhcping sends a single targeted DHCPREQUEST or DHCPINFORM packet at a specific DHCP server...
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Replaying PCAPs in Scapy: Packet Injection, Address Rewriting, and Timing-Accurate Retransmission
Manny FernandezObjective: This guide shows how to use Scapy to load a .pcap file and retransmit its packets onto a live...
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ipcalc Deep Dive: Mastering Subnet Math Across Every Linux Implementation and Homebrew
Manny FernandezExecutive Summary ipcalc looks like a single, predictable command, but at least three functionally different programs answer to that name...
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Creating and IP Addressing Scheme Design
Manny FernandezObjective: Give you a repeatable method for designing an IP addressing scheme that scales, summarizes cleanly, and doesn’t need to...
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FortiSwitch Upgrade Status Messages: A FortiLink Field Reference
Manny FernandezYou kick off a FortiSwitch firmware push from the FortiGate switch controller, and the status column just sits there. Is...
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Using FortiExtender as a Terminal Server
Manny FernandezThis post was take from a document I created for a customer. In my lab, I used a FEX200F which...
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FortiExtender 511G Deployment Guide
Manny FernandezExecutive Summary This guide deploys a FortiExtender 511G (FEX-511G) as a cellular WAN extension for a FortiGate 120G running FortiOS...
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Limitations of an AWS Peering Connection
Manny FernandezI had a customer over the weekend that has two VPCs (VPC-A and VPC-B). He created a peering connection between...
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TCP Flags Deep Dive: Meaning, Behavior, and Troubleshooting
Manny FernandezObjective: This guide breaks down all nine TCP control bits, traces exactly how they combine across a connection's lifecycle from...
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FortiGate Packet Capture: The Complete Advanced Filter Syntax Reference
Manny FernandezEvery filter you can type into the Advanced field is standard BPF, the same syntax tcpdump and diagnose sniffer packet...
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Where does the “Sequence Group” live in the FortiGate CLI Config
Manny FernandezDo you use Sequence Groups In your Firewall Policies? I absolutely love them. I used to use them in Checkpoint. ...
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Removing NAG Screen on Wireshark 4.6.7
Manny FernandezThe other day, I opened my Wireshark for macOS and found some ads and some nag stuff about donations and...
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Building a GRE Tunnel Between a FortiGate Firewall and a Cisco Router
Manny Fernandez1. Executive Summary Objective This guide walks through the end-to-end deployment of a Generic Routing Encapsulation (GRE) tunnel between a...
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Cisco ASA and FTD Encryption Schemes. What is supported on what version : The Complete Reference
Manny FernandezIf you have ever tried to stand up a site-to-site tunnel between an ASA running 9.8 code and a newer...
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Mastering FortiGate Service Objects: Custom Services, Groups, Categories, and the Options Nobody Uses
Manny Fernandez1. Executive Summary Objective This guide takes the FortiGate service object from the five fields everyone knows to the full...
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FortiGate Firewall Policy: Every Option set ? Will Show You
Manny FernandezThe FortiGate GUI shows you maybe forty percent of what a firewall policy can actually do. The rest lives in...
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The FortiGate Interfaces You Never Created: naf.root, ssl.root, and Every Default VLAN Explained
Manny FernandezVersion target: FortiOS 7.6.x, with behavior flagged where 7.0 / 7.2 / 7.4 differ. Commands are shown from the CLI....
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Standardizing FortiGate Interface Roles: LAN, WAN, DMZ, and Undefined
Manny Fernandez1. Executive Summary Objective This guide establishes a deterministic, auditable interface role standard across a FortiGate estate and explains precisely...
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Mastering FortiGate SSID Settings: Traffic Mode, Security Mode, Broadcast Suppression, Quarantine, VLAN Pooling, and NAC Profiles
Manny Fernandez1. Executive Summary Objective This guide walks through the six SSID settings that determine how a FortiGate-managed wireless network actually...
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Deploying FortiClient on Ubuntu Linux: The Complete CLI Reference for Desktop and Headless Endpoints
Manny Fernandez1. Executive Summary Objective This guide takes an Ubuntu 22.04 or 24.04 LTS host from bare OS to a fully...
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