Client Devices Dropping/Not Connecting After Firmware Updates

[ChrisK]

I am by no means a network engineer, but I'm learning as I go...

I recently updated our FG100E, FortiSwitches, and FAPs to current versions and it has broken so many things, it seems. I couldn't say exactly what version I started off at with each device, unfortunately. I'd take everything back, if I could. 

I updated the FG to 7.2.4, the switches to 7.2.3, and the APs to 7.0.0 after confirming that these versions were compatible. I also followed upgrade paths for all devices provided. 

Currently, it seems like my APs have much less reach in regards to signal strength. We also have many printers and wifi thermostats that keep disconnecting. I can't tell if this is due to the signal strength or some other issue that I can't pinpoint. I also have a number of Windows devices with connection issues, now.

I have downgraded APs to 6.2.2 in an attempt to resolve this. No luck.

I have downgraded the switches to 7.0.6. No luck.

My next thought is to take the FG back to 6.2.x, but I just really don't know.

Has anyone dealt with this? Is there a way I can see what version I started off on and get back to that? 

[gfleming]

You need to properly diagnose the problem before you start just randomly downgrading things. Also note most of the intelligence comes from the FortiGate with regards to switching and wifi.

Back to point #1, does this affect only wifi devices? 

What is your power settings on the FortiAP profiles?

What model of FortiAP are you running?

[ChrisK]

I have been working with Fortinet support and doing my own troubleshooting to diagnose the issue. With this disabling a good portion of my network, I needed to attempt changes. My downgrades were not random. I checked for compatibility and confirmed with Fortinet support before processing them.

I have determined that this only affects the 2.4ghz radios. All 5G devices connect and function without issue. Older computers, most printers, and all of our wifi thermostats use the 2.4 band.

The power is set to Percent - 100%.

These are FAP-U431F units.

Thank you!

[gfleming]

Setting power to 100% is almost always a bad idea. The APs transmit much higher than any device will. So the devices will hear the APs but the AP won't hear the devices. Also at 100% the chance of co-channel interference increases.

https://docs.fortinet.com/document/fortiap/7.2.4/fortiwifi-and-fortiap-configuration-guide/68434/sig...

Can you try reducing the power of your 2.4ghz radios to 10-14dBm and see how it goes?

[ChrisK]

I see. I will make this adjustment on my test pool and report back. 

[ChrisK]

I switched the AP profile over to dBm, and set it to 14. Once it took affect the remainder of my 2.4ghz devices dropped off the network.

Fortinet support has determined that the issue resides between the AP and the switch. The client sends a request, the firewall responds, then the firewall never receives a response from the client. I'm in the process of sending debug files for their engineer to troubleshoot. They believe the packet is being dropped somewhere. 

[gfleming]

OK interesting that setting your power to 14dBm dropped all clients though. That sounds more like an AP/wifi thing to me.

Did any clients ever reconnect at 14dBM or were they off for good until you upped the power?

[ChrisK]

All devices stayed offline. When I restored the original power, the select few devices re-joined the network. It's still very spotty. I really thought this was a signal strength issue. Some devices that had no issue with connection previously are showing lower signal strength after these updates. I have been through several versions of FAP firmware with no relief, however.

[sw2090]

Did you follow the recommended upgrade path?

[ChrisK]

I did follow the upgrade paths provided by Fortinet.