MAC address conflict: Received packet claiming to be from our MAC address

Peplink 20x (Balance-D660) is showing a regular stream of this message in the event log:
MAC address conflict: Received packet claiming to be from our MAC address (our LAN mac address)

I saw one other post where it may be a networking loop, but I wanted to see if that is the common thought or if there are other ideas about what is causing this. It does not appear to be causing problems on the network, but I want to clear it and be sure it’s not.

The only time I have seen this message is when I had some meshed APs start acting up.

I imagine that thing is running a bit slower than usual.

If you have manually set any Mac addresses on the network, make sure that you didn’t accidentally assign the same address as you router.

We use the internal AP but not a mesh of devices. No MAC addresses are manually set, nor do devices appear in the client list with the same MAC. The event log does not show a consistent pattern. It may show about 30 log posts in 2-3 minutes, and then it won’t show anything for 45 minutes.

@FlyingPreacher, One of your LAN devices is causing the issue. I had this same thing happen a few months ago when they turned this option back on in the event log. I was able to track it down to one of the IP cameras I had installed. Not sure why it was having an issue, it was a really old camera, but as soon as the network cable was unplugged the issue went away.

Not sure how many devices you have, but I started at the router and worked my way back, unplugging each cable, then the switches, and then isolating it to the exact device. Hope this helps.


Hi have you managed to solve this issue? I’m having the same issue with my Peplink Balance one.

I just found that mac address is Peplink’s LAN Mac.

how to solve this issue?

I am having the exact same issue. Considering it’s not an IPv4 address, I’m unsure how to track it down or why it’s even conflicting with a Peplink MAC.

The router can create a network trace, perhaps also called a Wireshark trace or a pcap trace. The router can do this all by itself. This logs all the bits in and out and seems the obvious next step.

Go to
(where is router IP address) and there is a simple checkbox for network trace. Run it a bit and then stop it. The trace can be downloaded on its own, but probably best to create a diag report which should include the trace data.
Then, open a ticket.


@BeachComber1 @mohanreddy4u,

Its most likely a hard wired network device. I found the easiest way to fix the issue on site was by opening the event log, and then unplugging each network cable connected to the router until the event stopped. Once I figured out what was plugged into that port, I went to the next device in line which was an unmanaged switch. I started unplugging cables one by one until the event stopped. I was able to pinpoint the issue down to an old wired network camera. Not sure why it wasn’t picking up an IP address, but once disconnected, I haven’t had the issue since.

As it not continuous it’s hard to catch in real time to unplug cables.

Above pic was only times it happened today. Almost impossible to get to router and unplug in the timeframe.

Rather than touching the router to unplug cables, you can remotely access the router and disable one LAN port at a time. On a Balance 20x: Network tab → Port settings. If a dumb switch is plugged into a LAN port then, I suppose, you have to physically unplug the devices to find the bad one.

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I have a Dell x1052p plugged into the Balance Router with bonded lan between the two.

And then again, it could be coming from a WiFi client I guess.

I am now getting this error and it lines up with my entire LAN locking up, and both of my (TPLINK) switches requiring a reboot along with the peplink to clear the error. With 100’s of devices on my LAN this is going to be very painful to debug. Is there any way to get extended error messages on these that might expose the IP address that is causing the MAC conflict?

It isn’t likely to be an IP- or rather, it will probably be the Peplink’s IP.

If the Peplink says its getting packets back with its own MAC, it’s most likely to be a loop somewhere, so the peplink it getting send back packets it itself sent… ie a loop, rather than a faulty or rogue device sending them itself (although that is possible).

Access Point’s that allow meshing temporarily/sometimes meshing and causing loops is something I have seen before.


VOIP phones can sometimes cause this issue. If someone has plugged the the wall socket into the lan (usually used for connecting a laptop/pc) port on the phone instead of the wan/internet port.

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Thanks for the pointer. When this happened again this past weekend i took out my eero wifi modules one by one until I found the one that was causing the problem. It was a gen 1 eero that is now being recycled.

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Hey @grahamk :<) :,) :,)

  • Rick

Hi Rick! Hope you have been well.

I have really been impressed with eero since buying them from their initial kickstarter campaign. Super great support and very seldom any need to use it. Much like peplink. But not any more - ever since AMZN bought them. My network is still having these issues that are only solved by visiting each eero and power cycling them (I am currently running 6). App cant get to them to reboot because, well, because they have frozen my network somehow. I opened a support case with them over 3 weeks ago and still have heard nothing back. So i would never recommend eero to anyone these days.

But man, I looked into these peplink mesh AP’s and it would cost me over $1500 to replace my eeros with these. So for now, i’m going to have to stay put. But it’s on the list should i ever get a nice cash windfall or something. Thanks for pointing these out - I was not aware that peplink made these…

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anyone with the issue have IGMP snooping enabled?