[USG Flex 100H] - DHCP not release any IPs for Interface (randomly)

Maverick87

Hi Melen,

Today I had another problem with IP addresses not being released by the DHCP server within the interface.
I'm attaching the debug log, and this is the configuration of the interface in question.
This interface is used by a Wi-Fi access point (Zyxel NWA130BE, not connected to Nebula, therefore managed locally). Every device attempting to connect to the access point was rejected, generating IP issues. Furthermore, the access point was not responding to ping requests.
Disabling and reactivating the interface (cicling between inactive and active) rebooted the interface and thus also restarted the DHCP server.
After this step, the access point is pingable, and every device attempting to connect now has no problems and connects normally.

I've two SSID configured with two different VLAN ID (main SSID and IoT Devices SSID), and, if you see the AP log it's strange that for the other SSID I don't have any connection, seems as the Access Point device was freezed and was "unblocked" only when I restart the "main" interface.

Can you assist me?

Thank you,
Valerio

log-debug-2025_09_15.xlsx

Main WLAN Interface:

IoT WLAN Interface:

It's so strange that for the Access Point, I've, for today, only the logs that starts from 09:14, when I've restarted the main AP interface.

Main SSID:

IoT SSID:

Zyxel_Melen

Hi @Maverick87

From the AP's log, this looks like the AP might have issue during the issue.

Could you help to collect the AP's diagnostic file? We will check it to see if we can find any cules in it. If we can't, we will need your help to collect it again when the issue occurs.

https://community.zyxel.com/en/discussion/18869/how-to-collect-the-standalone-ap-diagnostic-info-by-gui

Maverick87

Hi @Zyxel_Melen thank you for your reply.

I cannot attach here the AP Diag Log because the extension is tag.bz2, and if I decompress into tag is the same.
How can I attach the file?

Thank you

Zyxel_Melen

Hi @Maverick87

Please help to zip it before attaching the file in the private message. I will send you a new message for the request.

Maverick87

Hi @Zyxel_Melen

I've uploaded the file in your link.
Today, seems that I've a problem only with my IoT SSID, I've more or less 25 IoT Devices, but only 1 is showed into the AP Station List :(

As always, after circling disable/enable of the interface:

I collect the the diag of the AP and also All logs of the firewall. I upload it in the private message as before.
At 07:53 more or less I've switched the IoT LAN off and on, in the logs you have the first boot and also the moment in which I've restarted IoT LAN.

Maverick87

Hi @Zyxel_Melen

today seems that all works perfectly.
I've sent to you (in private) all the logs, so you can compare it to the others.

Thank you for your support