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meliodes
meliodes
New Member
May 6, 2022
Question

Switch blocking uplink to FG80F after 6.4.9 update

  • May 6, 2022
  • 9 replies
  • 9485 views

Last night I updated my Fortigate 80F from 6.4.8 to 6.4.9 and immediately lost connection to the LAN. I could still ping the Fortigate from the internet side, so on a hunch I checked the switch (a Unifi 24PoE) and noticed the port the 80F is plugged into was blocked. Disabling STP on the port makes everything work again. I'm not sure if it's a Ubiquiti problem or a Fortigate problem, but it had been running fine on 6.4.8 for months. There's only one connection between the 80F and the switch. RSTP priority on the switches is set to 4096 on the 24PoE and 8192 on a couple of downstream switches. I skimmed the release notes for 6.4.9 and nothing stood out that might cause this kind of issue...any ideas?

9 replies

A
Anonymous_User
New Contributor III
May 9, 2022

Hello meliodes, 

 

Thank you for using the Community Forum. I will seek to get you an answer or help. We will reply to this thread with an update as soon as possible. 

 

Thanks, 

 Fortinet Community Team 

A
Anonymous_User
New Contributor III
May 9, 2022

Hi meliodes,

 

That issue would require in-depth investigation, and that would be best for you to create a support ticket for that to know the root cause. 

 

Hope this helps!

 

Regards

RJ 

Jeffcander
Jeffcander
New Member
June 9, 2022

I have come across the same issue.  Did you ever get this resolved?

jweisz
jweisz
New Member
June 13, 2022

This just took down our entire network. I can't find any mention of spanning tree in the release notes for 6.4.9, and a technical tip in 2020 claims that FortiGates don't participate in STP, but... apparently they do now? You can switch STP off on the FortiGate interface, and you should be back in business.

alif
Staff
alif
Staff
June 13, 2022

Hello @meliodes,

 

Please check if STP is enabled on the port that is connecting to Unifi switch.

 

config system interface

edit <interface_name>

show full | grep stp

 

If the above output shows STP is enabled, then this could be the reason that you lost access to the LAN.

jweisz
jweisz
New Member
June 13, 2022

@alifThe issue in this case is not that STP is enabled (obviously, it is for this issue to occur). The issue is that STP was enabled (no config change) in 6.4.8, and did not cause this issue. So something about the 6.4.9 release changed STP functionality, and I don't see anything documented in the release notes. I am unsure if STP was just broken in 6.4.8, and 6.4.9 fixed it, or if some other change adjusted how STP determines if it believes there's a loop.

 

Fortinet needs to identify and document the related change.

alif
Staff
alif
Staff
June 13, 2022

I did find an internal Engineering ticket that has a similar issue reported after firmware upgrade from 6.4.8 to 6.4.9. It's still being investigated and currently no fix is available.

MattPolichany
MattPolichany
New Member
June 16, 2022

I'm having this issue as well on 7.2.0

Altice
Altice
New Member
August 31, 2022

Any update about this issue? i have exactly the same problem... The same version 6.4.9 on others equipments.

alif
Staff
alif
Staff
September 3, 2022

The issue has been resolved in FortiOS 6.4.10.

It's mentioned in the "Resolved issues" section of FortiOS 6.4.10 release notes.

809366 - FG-40F with STP enabled on a hardware switch creates a loop after upgrading to 6.4.9.

https://docs.fortinet.com/document/fortigate/6.4.10/fortios-release-notes/289806/resolved-issues

syordanov
Staff
syordanov
Staff
September 5, 2022

Hello meliodes,

 

I think are  hitting bug No 0809366 which is fixed on 6.4.10.

 

dovid
dovid
New Member
May 7, 2023

I am not sure if this is related but I seem to be having this issue in 7.0.11. I am using a FWF-40F. It only happens when using a software switch. When I use a physical interface there is no problem. When I do a tcpdump on the interface that is associated with the software switch I see a bunch of STP packets coming out of the FortiNet device.

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