network duplicate ip


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my router tells me i have 2 devices using the same ip.

the ip is used by unraid server.

I can't find the other one.

arp -a on a lan host return unraid ip with an unknown mac address. 

I can see the mac address in unraid with ip link and it's attached to [email protected]

i use one physical interface

i have only one vm running with a different mac address.

I have dockers running and one has a different ip (heimdall)

what can be this mysterious device?


edit: from my understanding, considering the interface [email protected] it should be a docker on custom network but i can't find it

Edited by caplam
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  • 1 month later...



the problem is still present and i wonder if that's why transfer speeds with smb to macos is pretty damn slow (40min to transfer 5Gb)

the mac address  detected by the router are the physical adress of the adapter and a mac that seems tied to docker.


289: [email protected]: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP mode DEFAULT group default qlen 1000
    link/ether 46:8a:aa:36:26:bf brd ff:ff:ff:ff:ff:ff


notice : the address has changed since my last post

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  • 6 months later...
  • 2 months later...

From what I can work out, with Docker setup to Host Access to custom networks, you get a second network appearing on the same Server IP address.  I have 2 NICS, one for the docker vlan one for the server management, both show two networks/MAC addresses at the same IP. Hasn't degregaded performance.


What would be nice, and I'm not sure if possible, is to fix/lock a MAC address in for br0 so that my network controller can label it properly.  It seems to change at every reboot.  It's not a performance thing or show stopper, just helps my OCD cope with my network controller better.

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  • 2 months later...

I have the same issue. I keep getting notifications from unifi controller that there are duplicate IP addresses on my network. Upon checking it it is the shim-br0 interface that is using the same IP address as unraid. I want to know if there is a way to get rid of this as disabling the notifications on this warning is not a solution for me!



2023-01-19 09_03_57-UniFi Network – Mozilla Firefox.png

2023-01-19 10_32_46-root@TEVENAS_ ~ _ bash --login (TEVENAS) – Mozilla Firefox.png

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