Controller shows unknown 'Known Clients'

Controller shows unknown 'Known Clients'

Controller shows unknown 'Known Clients'
Controller shows unknown 'Known Clients'
2025-06-07 14:06:45
Model: OC200  
Hardware Version: V1
Firmware Version: 1.35.7 Build 20250514 Rel.51837

Hi @Vincent-TP, already since last year my OC200 controller regularly displays unknown clients in the overview of Known Clients. These all have a MAC Address starting with "C0-A8-0x". I posted about this earlier but unfortunately you where not able to further investigate or assess this. Also see Controller shows unknown 'Known Clients'.

 

 

My setup:

  • 1 x OC200 v1.0 controller (firmware 1.35.7 Build 20250514 Rel.51837)
  • 1 x ER605 v2.0 router (firmware 2.2.6 Build 20240718 Rel.82712)
  • 2 x SG2210P v5.20 switch (firmware 5.20.10 Build 20250307 Rel.72554)
  • 1 x ES205G v1.0 switch (firmware 1.0.3 Build 20250414 Rel.72933)
  • 5 x EAP615-Wall(EU) v1.0 access points (firmware 1.5.0 Build 20240830 Rel. 63168)
  • 2 x EAP225-Outdoor(EU) v1.0 access points (firmware 5.1.7 Build 20240819 Rel. 44148)
  • 2 x EAP230-Wall(EU) v1.0 access points (firmware 3.2.3 Build 20240815 Rel. 33684)

 

Even though I regularly "forget" these clients, they keep appearing every now and then. My network is properly secured with ACL's, IP-MAC Binding, etc.

 

None of these MAC Addresses are known to me. All my (30+) wired clients have a fixed IP address using DHCP Reservation, in combination with IP-MAC Binding. My (also 30+) mobile clients all have a dynamic IP address. I disabled random MACs of my known mobile clients to access my home network, as an extra layer of security using MAC Filter to only allow known clients.

 

What at least is remarkable is that these all have a MAC Address starting with the same range "C0-A8-01". Obviously, I checked if any of my wired and wireless clients have MAC address that looks similar, which is not the case.

 

The only thing I can think of is that these are "temporary" (or actual?) MAC addresses of the access points, since many of these have a MAC address starting with the same range ("40-ED-00" for all 5 EAP615-Wall access points and "84-D8-1B" for all 2 EAP230-Wall access points). And yes, I checked if there is any MAC address starting with "C0-A8-01" in the wired client list; there is none. That is why I was suspecting the access points.

 

Do other users have this as well, and does anyone know what is causing this?

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#1
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18 Reply
Re:Controller shows unknown 'Known Clients'
2025-06-09 00:45:43

  @WM1 When i remember correctly, this is cause by some WLAN Optimization options. Maybe it was 802.11r

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#2
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Re:Controller shows unknown 'Known Clients'
2025-06-09 08:20:19

Hi @pustekuchen, thanks for your response. Did you also have this issue?

 

I don't think it is related to 802.11r since I don't have that option enabled in any of my four SSID's.

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#3
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Re:Controller shows unknown 'Known Clients'
2025-06-09 09:15:30

Hi  @WM1 

 

Sorry for missing your previous message.

 

Please go the following page of the controller, and input iwconfig command, and check if there is any similar MAC address in the results. 

Or you can send us the results to check.

 

 

 

Please perform the operation on each EAP model individually.

 

 

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#4
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Re:Controller shows unknown 'Known Clients'
2025-06-09 19:21:24

Hi @Vincent-TP, I checked with iwconfig for the wireless network interfaces of each EAP individually.

 

For the different SSID's which are broadcasted either the MAC address of the EAP is shown or the MAC address of the EAP +1 is shown. Meaning, either 40-ED-00-E7-40-22 or 40-ED-00-E7-40-22, or either 40-ED-00-E7-4C-AC or 40-ED-00-E7-4C-AD. I also checked with ifconfig for the wired network interfaces of each EAP individually. 

 

None of the MAC adresses are even close to the range "C0-A8-01", which are the ones shown under 'Known Clients'.

 

Can this maybe come from the OC200 v1.0 controller, the ER605 v2.0 router or one of the SG2210P v5.20 switches? Do you maybe have a command to check any of these?

 

(It cannot come from the ES205G switch since I recently added that to my setup and I already noticed this behavior beforehand.)

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#5
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Re:Controller shows unknown 'Known Clients'
2025-06-11 01:53:27

Hi  @WM1 

 

Thanks for that info.

 

One more thing, will these MAC addresses show up on the insight - past connection page? If yes, please check which devices are they connected to via AP/PORT column.

 

 

 

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#6
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Re:Controller shows unknown 'Known Clients'
2025-06-11 20:23:54

Hi @Vincent-TP, indeed that is where these show up as well. I downloaded the data of this month to sort on username. This is the result:

 

 

I added one extra column (yellow) to mention what device is connected to these switch ports.

 

To further clarify:

  • Only Switch 1 and 3 are connected to the Router
  • Switch 2 is connected via fiber to Switch 1
  • Access Points 1 to 6 are connected to the PoE ports of Switch 1
  • Access Points 7 to 9 are connected to the PoE ports of Switch 2
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#7
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Re:Controller shows unknown 'Known Clients'
2025-06-11 21:37:27 - last edited 2025-06-11 21:39:59

I can confirm sort of the same behavior in my environment.

 

Port 6 + 7 -> EAP655-Wall(EU) v1.0

 

The MAC-Adresses of 2,4/5 GHz of EAP (Port6) are 

AE:25:4A:84:DB:F4

AE:25:4A:84:DB:F5

 

The MAC-Adresses of 2,4/5 GHz of EAP (Port7) are 

AA:25:4A:84:DB:C4

A2:25:4A:84:DB:C5

 

If you take a look closly, you can see that the Part 4A-84-DB in the middle of the EAPs MACs are the beginning the the appearing MAC-Adresses.

 

I have another EAP on Port 4, which have another MAC-Adress Range - but same behavior.

 

@WM1 Do you have OFDMA enabled?

 

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#8
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Re:Controller shows unknown 'Known Clients'
2025-06-12 02:45:00

Hi  @WM1 

 

Thank you so much for taking the time to post the issue on the TP-Link community!
To better assist you, I've created a support ticket via your registered email address and escalated it to our support engineer to look into the issue. The ticket ID is TKID250622011. Please check your email box and ensure the support email is well received. Thanks!
Once the issue is addressed or resolved, please update this topic thread with your solution to help others who may encounter the same problem as you did.
Many thanks for your excellent cooperation and patience!

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#9
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Re:Controller shows unknown 'Known Clients'
2025-06-12 19:09:11

Hi @pustekuchen, yes I have enabled OFDMA on the EAP615-Wall(EU) v1.0 access points that support it. The EAP225-Outdoor(EU) v1.0 and the EAP230-Wall(EU) v1.0 access points don't suport OFDMA. Do you think that this could be the origin of the issue?

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#10
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Re:Controller shows unknown 'Known Clients'
2025-06-12 19:22:34

Hi @Vincent-TP, you're more than welcome. Thanks for the support. I received the instructions and I will following the steps to allow your team to further investigate the issue. 

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#11
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