Remove VLANs from Fortiswitch ISL Trunk

[jprocha]

Hello everyone!

I would like to know if there is a way to exclude specific VLANs from passing inside a fortiswitch ISL trunk or to pass only management traffic between a specific ISL link.

By default fortilink passes all VLANs between Fortiswitches connected to each other. Yet, I have a requirement to not allow specific VLANs to pass through a ISL formed between 2 FortiSwitches, therefore forcing data traffic to go through a 3rd party switch connected to both of these Fortiswitches.

KB: https://community.fortinet.com/t5/FortiSwitch/Technical-Tip-Seperate-Inter-Switch-Link-ISL-between-M...
states about separating the traffic, but my requirement does not need the second link to pass data. Is there a simpler way to achieve this? Did not want to go into modifying MSTP instances and all of that.

Thanks in advance for any suggestions and tips!

Regards

FortiSwitch 

[ebilcari · Accepted solution]

This article shows how to make static ISL for Fortlink trunk and manually select the allowed VLANs and may work also for ISL between switches. You can also remove auto-isl and manually configure trunks. If you have a pair of spare switches you can test it.