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DM6
DM6
New Member
March 13, 2026
Question

OT Application Signatures not persisting between reboots

  • March 13, 2026
  • 2 replies
  • 260 views

I have the OT Applications add-on for Fortigate FG-70F firewall. I can create a profile, activate the OT signatures and use them to create a modbus specific profile. The issue is that when the firewall is power cycled, the OT application signatures disappear, meaning my rule isn't working. I then need to manually turn off and on OT signatures in the profile to make the profile work. These firewalls are going to be isolated with only local access, so this is going to cause issues in the event we advise the customer to reboot the devices or another technician unaware of this issue performs a reboot during maintenance. Is there any fix for this issue?

2 replies

Anthony_E
Staff
Anthony_E
Staff
March 13, 2026

Hi,

 

Your version is maybe out of date. Could you pleaae first check it:

 

diagnose autoupdate versions | grep Application -A 8

 

Once you have the version,  manually update the FortiGuard server :

 

diagnose debug application update -1
diagnose debug enable
execute update-now

 

And save:

 

execute save

 

Regards,

Best Regards
DM6
DM6Author
New Member
March 13, 2026

Hi Anthony, 

I get the following when running the grep command 

 

Application Definitions

---------

Version: 35.00175 signed

Contract Expiry Date: Mon Sep 23 2030

Last Updated using manual update on Mon Mar  2 14:52:32 2026

Last Update Attempt: Fri Mar 13 08:19:56 2026

Result: Connectivity failure

 

GenAI Application Definitions

---------

Version: 0.00000

Contract Expiry Date: Mon Sep 23 2030

Last Updated using manual update on Sun Dec 31 23:00:00 2000

Last Update Attempt: Fri Mar 13 08:19:56 2026

Result: Connectivity failure

 

OT Threat Definitions

--

Proxy Application Definitions

---------

Version: 35.00175 signed

Contract Expiry Date: Mon Sep 23 2030

Last Updated using manual update on Mon Mar  2 14:52:32 2026

Last Update Attempt: Fri Mar 13 08:19:56 2026

Result: Connectivity failure

 

The Fortigate won't have any internet access and is to remain isolated, so its preferable that I can do updates manually, which I've been doing by getting the update packages via Forticloud. 

DM6
DM6Author
New Member
March 18, 2026

Hi Anthony, I tried the above, but didn't have any luck. The firewall still loses the OT signatures when power cycled. Any other things I can check to fix this?

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