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Question

ESXI Fortigate VM issue

Forum|Forum|4 months ago
March 17, 2026
12 replies
493 views

I installed the ESXi version of the FortiGate VM and added the FortiSwitch under FortiLink. However, the logs keep showing the following error. how can I resolve it??

FortiLink: ISL timing-out for trunk(XXX) member port(24) did not receive ISL pkt for(10) sec

Fortigate-VM

AEK

SuperUser

Try follow this guide.

https://community.fortinet.com/t5/FortiGate-Cloud/Technical-Tip-Setting-up-FortiSwitch-FortiLink-Management-using/ta-p/318464

AEK

52000ccAuthor

New Member

this for hyper-v, but I am using vmware esxi.

funkylicious

SuperUser

hi,

i think that the network that you connect to the VM has to be either a trunk in ESXi and native w/ 4094 on the switch or directly tagged with 4094, since fortilink uses 4094 but this can be changed on the FGT / FSW - https://community.fortinet.com/t5/FortiSwitch/Troubleshooting-Tip-Change-FortiLink-management-vlan-from-4094/ta-p/380256

"jack of all trades, master of none"

52000ccAuthor

New Member

the currently fortigate vm port on esxi vlan setup as 0, will untagged traffic, do I need to make it change to 4094??

funkylicious

SuperUser

no, if its configured as trunk and allows all vlans on esxi side is fine.

have you tried enabling promiscous mode/forged transmits settings on the network in esxi ?

also, is the host directly connected to the switch that you are trying to add/manage via fortilink or via another one?

"jack of all trades, master of none"

52000ccAuthor

New Member

promiscous mode/forged transmits settings all three on the network in esxi is enabled.
the host is direct connect to the switch via that port.

funkylicious

SuperUser

https://community.fortinet.com/t5/FortiSwitch/Troubleshooting-Tip-ISL-timing-out-message-FortiLink-ISL-timing/ta-p/337830

tldr on the FSW enable static-isl;

config switch trunk
edit <>
set static-isl enable <----- Manually add this command.
end

"jack of all trades, master of none"

52000ccAuthor

New Member

failed as below error
set static-isl enable

command parse error before 'static-isl'
Command fail. Return code -61

funkylicious

SuperUser

try creating a software switch with that single interface and enable fortilink by doing , set fortilink enable in the cli for the software switch, on the FGT and then see what happens.

"jack of all trades, master of none"

52000ccAuthor

New Member

My current switch is showing as green on fortigate. If I switch to a software switch, will I need to delete and re-add it? Also, what impact does the error log have?

funkylicious

SuperUser

there will be downtime, yes.

as for the error log, what impact does it have now? if everything works as intended and you just wanted to know what it means, then i think that you can ignore it.

"jack of all trades, master of none"

52000ccAuthor

New Member

I don't know its impact, this switch is newly added, so the log keep filling on the fortigate, just like fortigate will lost connection of the switch in sec.

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