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DHCP binding shows more IP released but wireless Clients are half of that

  • 9 January 2019
  • 8 replies

Dear all.
I have got an issue with AP7502 which is running with wing and enabled One AP as virtual controller having 20 APs adopted.

I have enabled DHCP in the virtual controller and its working fine.

The issue what we are facing is the DHCP binding table shows more IP's than wireless clients.

I have duly checked the DHCP binding after disabling wireless SSID whether the DHCP is getting released through LAN. But no IP's are getting released through LAN, only when SSID is enabled the clients are connected and DHCP binding table is being filed.

Once the clients becomes 65 we can see the same time DHCP binding table will be 90.

The DHCP lease time now kept as 4 hours. But we tried by reducing the lease time to 1 hours also.

Is the issue is with the AP "not showing with correct Clients list" or how this DHCP IP's are being released with no information in the client list but only happens when wireless radio is enable.

Kindly requesting to help me with the solution.

Thanks & Regards
Abdul Raheem

8 replies

Userlevel 6
You can try seeing if number match up between GUI & CLI,
here is CLI command " show ip dhcp binding"
Dear Robert
Thank you very much for replying.

I was duly checking the same way you have mentioned. "show ip dhcp binding all" and also the clients in GUI and using CLI "show wireless clients".
Then only I have posted the message.
Userlevel 6
What's the lease time?

It's possible that, for example, there were a total of 90 clients that REQUESTED an IP....but then 25 'left' the WLAN...thus only leaving 65 actively connected.
In which case, if those 25 did not send a DHCP Release, then they will continue to consume an IP lease until the lease time expires on the DHCP server.
Dear Chris
Thank you very much.
The lease time is 4 hours.
Do we have any CLI commands in Wing AP's to find the wireless clients history for last 24 hours or last one or two days?
Userlevel 6
What specific history information you looking for? There are many commands for looking at client information.
Hi Chris
Commands for getting what time a client connected to WLAN with its MAC, and the duration of the client connected to WLAN.

Suppose I am looking the client list today, yesterday who all are connected to the WLAN etc.
Userlevel 6
There's not a command for looking at a full history of all previously associated clients (in the same output window) within the controller itself. This would be a function of NSight. Either the CLI or GUI will obviously give you a listing of currently associated clients though....along with a detailed list of various metrics.

But, what you can do is look at a single client's association history, one at a time, using the command syntax:
sh wireless client association-history (Info also shown in the GUI)

The results don't include an actual Duration column, but it does have a Delta Time...so that you can see each time it was associated and the time period between associations.
Hi Chris
Thank you very much for your valuable feedback.