FortiAP FP431F 7.2 | WPA Enterprise - DHCP Not working

[MartinDf121]

Dear team, our office has an issue with the Secure corporate WiFi in one of the Access points.

It appeared right after a power outage.

So basically anyone who tries to connect gets APIPA.

Mind that the Guest which is Running Fine - WPA Personal.

Here are some screen shots of the logs - FortiAP Logs

The AP is connected to a Switch which has proper config on the interface, in-fact the rest of the AP's are on the same switch and have the same config on the interface and they are all working fine.

*Two weeks ago I have encountered the same issue in a different office with the same FortiAP model and Firmware - Mind that firmware update did not fix it. 

[ndumaj]

Hello @MartinDf121 

Thank you for your quick prompt,
No problem, take your time.
Waiting for your results.

BR

[MartinDf121]

Hey I have tried it and the AP is assigning the right VLAN - 100 -

But the computer keeps getting APIPA, this is very strange, like it was working a week ago...

[ndumaj]

Hello @MartinDf121 
DHCP for vlan 100 is configured on FGT, correct? If the VLAN is assigned properly then the host should get the IP.
Did you try to manual disconnect the host from SSID and connect again does it get the proper IP from VLAN 100?

Check on FGT is it receiving DHCP packets, and what is replying?
PCAP on the host and FGT will provide more info why the host is not getting IP from DHCP server.

BR

[MartinDf121]

I have tried to connect the host to a different AP and it works.

I can see in the logs of the AP with the issue that it is receiving DHCP requests and sends offers but the host replies with more requests instead of accepting.

Mind that I have already checked the managed switch and the configuration of the interface that the AP is connected to is correct.

I have checked the Fortigate itself for the specific hostname and did not see DHCP packets regarding the VLAN

[ndumaj]

Hello @MartinDf121 
we need to compare the PCAP from both, working and non-working AP.

It looks like an issue with AP communication?!
I'm not sure if there is any issue with CoA, that's why I said, did you try to manually disconnect the host after successful authentication?

BR

[ndumaj]

Hello @ornaldo7 

Issue 0923964 is related to FAP - 43xF - "Clients won't ACK DHCP packet transmitted by AP"
Did you try to use the AP on version 7.2.0?
Also, try to disable 802.11ax.

BR

[MartinDf121]

Hi, We have found a solution (but we'll see for how long it lasts).

basically we have changed the build of the FortiGate's firmware from 7.2.8 to 7.4.4 and also upgraded to AP's to 7.4.3 and now it works

[ndumaj]

Hello @MartinDf121 
Nice to hear that you found a workaround, so a stable FortiOS combination that is stable.
I guess if it works, there is no reason not to be stable.
However, let's observe the situation.

BR

[Crow78]

I had the same issue today, dhcp was on and working but the Clients did Not get ab ip adress from the dhcp. After disabling 802.11ax on each radio everything worked Fine.