FortiGate – Troubleshooting Guide Quick Reference

After many years of working and teaching FortiGate technology I decided to share my knowledge. I focus on troubleshooting. FortiGate – Troubleshooting Guide Quick Reference presents easy to understand techniques of troubleshooting on FortiGate platform. There are many debug command examples, which explain, how to read and understand the command output. The intention of the book is not to teach you how presented technologies work. I do not explain configuration examples but if you do not feel confident to perform troubleshooting effectively, the book is for you.

https://www.amazon.com/dp/B087F95WFT

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What should you know about HA 'override enabled' setting on Fortigate?

High availability is mandatory in most of today's network designs. Only very small companies or branches can run their business without redundancy. When you have Fortigate firewall in your network you have many options to increase network availability. You can use Fortigate Clustering Protocol ( FGCP ) or Virtual Router Redundancy Protocol ( VRRP ). FGCP has two modes: 'override' disabled (default) and 'override' enabled . I'm not going to explain how to set up HA as you can find many resources on Fortinet websites: https://cookbook.fortinet.com/high-availability-two-fortigates-56/ https://cookbook.fortinet.com/high-availability-with-fgcp-56/ Let's recap what is the main difference between them. The default HA setting is 'override' disabled and this is an order of selection an active unit: 1) number of monitored interfaces - when both units have the same number of working (up) interfaces check next parameter 2) HA uptime - an ...

FortiGate and GRE tunnel

Recently I worked on one project where a client requested to re-route web traffic to the GRE tunnel to perform traffic inspection. I would like to share with you what is required if you configure it on FortiGate. We need a new GRE interface and policy base routing (PBR) to change the route for specific source IPs. Of course you need firewall policies to permit the traffic. Let's start with GRE interface. Unfortunately you can't configure it using the GUI, only CLI is the option: config system gre-tunnel edit "gre1" set interface "port1" set local-gw 55.55.55.55 set remote-gw 44.44.44.44 next end When the end peer is Cisco router, you need to set the IP for the GRE interface: config system interface edit gre1 set ip 192.168.10.10 255.255.255.255 set remote-ip192.168.10.20 end In next step we need to fix routing. We need the alternate path via GRE but to keep the route in the active routing table you need to set the same AD (adminis...

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