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Ivan90
Ivan90
New Member
March 19, 2026
Question

Fortigate VM KVM port mapping

  • March 19, 2026
  • 2 replies
  • 273 views

Hello! There is a migration scenario where I am not sure 100% about the port-naming\mapping order.

I have 2 FortiGate VM in a public cloud (some local Open-Stack\KVM based vendor). My case is moving VMs between AZs and it can be done only manually. So for now I have 5 interfaces\ports on each VM and whey were configured in an adding order (I added one by one and got "port1, port2, port3" etc). In the migration process I'll have to stop the VM, save the image and redeploy in another AZ (like moving an HDD) and attach the image. I will create the same networks with the same IP parameters , but my concern is that when I power on the VM ports can be

1) the same 5, but mixed between each other

2)First 5 ports got "empty" and new start from 6 to 10

Both options are bad. Does anyone know anything about port naming\mapping and the correct order and how can I impact within KVM environment.  I couldn't find anything except several reddit's posts 7ish years old.

The ver is 7.4.11

Thanks!

2 replies

Markus_M
Staff & Editor
Markus_M
Staff & Editor
March 19, 2026

Hi Ivan,

 

interesting question. I'm not familiar with the environment, but do you see the MAC addresses the ports would have as well as the current ones? I would expect them to basically count up and as such have the portX assigned.

Ivan90
Ivan90Author
New Member
March 19, 2026

might be, but I am looking for an official proves. 

I can see MACs and they will be changed after migration. 

There is a solution that I could backup the config , deploy the new VM , plug ports and restore the config, but it's a long way and I am lazy. 

Markus_M
Staff & Editor
Markus_M
Staff & Editor
March 20, 2026

Not to be philosophical, but often the longest possible path is the shortest.

Of course, if somebody has an actual replicatable shortcut, happy for correction.

Ivan90
Ivan90Author
New Member
March 21, 2026

well, I did this. It was an absolutely nightmare ( literally , I was troubleshooting it till 5AM).

So if you backup the config and save the hdd state somewhere and then try to run this VM with mounted HDD and you didn't plug all ports (for instance on the public cloud which we use it's only possible to create a new VM with the only one port first and then you can add others) the FG VM64 will just remove all parts of the config related to unplugged interfaces. For instance if you had port 2 as an HA, port 3 and 4 for some traffic , it will be just removed from the config. I wont wait till you plug it , just removes from the config. I don't understand the logic , then I migrated a vendor "C.." VM with the same case , it waited till I plug all ports and all parts of the config were saved.  Something like this.

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