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DHCP assigned IP issue with Blue Cave as AiMesh router

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Mcdull

Occasional Visitor
I just got a Blue Cave to replace an RT-AC68U as main router in a 3x RT-AC68U AiMesh.
Then I'm seeing issue in getting manually assigned IP from DHCP:
1. if the devices are connected to the Blue Cave (main), they get the assigned IP
2. if the devices are connected to the other nodes, they get dynamic IP usually and they change between 2 IP.

In checking the client list in Blue Cave, what I noticed is all the devices connected to the same AiMesh node have a new MAC address, 3 first parts are the same for devices in the same node (they changed if the AiMesh node reconnects to main), the last 3 parts are the same as the original MAC. I have seen modified MAC when using Wifi Extender, didn't know it's also in AiMesh.
For the same device, 2 MAC and 2 IP (1 assigned, 1 dynamic) are showing up in the client list.
Anyway, I suspect Blue Cave uses the modified the MAC of the devices to assign IP and because the MAC do not match what are in the assigned IP table, so new dynamic IP are allocated.

I fallback to use RT-AC68U as main router (2x 68U and Blue Cave as node) and confirmed that this issue does not exist with 68U, each device has 1 IP in the client list.

I couldn't find any information of it in searching Internet (and there is no support email I can send the issue to).
Is it an existing problem? or new problem in new firmware?
 
I just got a Blue Cave to replace an RT-AC68U as main router in a 3x RT-AC68U AiMesh.
Then I'm seeing issue in getting manually assigned IP from DHCP:
1. if the devices are connected to the Blue Cave (main), they get the assigned IP
2. if the devices are connected to the other nodes, they get dynamic IP usually and they change between 2 IP.

In checking the client list in Blue Cave, what I noticed is all the devices connected to the same AiMesh node have a new MAC address, 3 first parts are the same for devices in the same node (they changed if the AiMesh node reconnects to main), the last 3 parts are the same as the original MAC. I have seen modified MAC when using Wifi Extender, didn't know it's also in AiMesh.
For the same device, 2 MAC and 2 IP (1 assigned, 1 dynamic) are showing up in the client list.
Anyway, I suspect Blue Cave uses the modified the MAC of the devices to assign IP and because the MAC do not match what are in the assigned IP table, so new dynamic IP are allocated.

I fallback to use RT-AC68U as main router (2x 68U and Blue Cave as node) and confirmed that this issue does not exist with 68U, each device has 1 IP in the client list.

I couldn't find any information of it in searching Internet (and there is no support email I can send the issue to).
Is it an existing problem? or new problem in new firmware?

I can't say I follow all of this. Something is likely not setup right.

Reset all routers before configuring the network. Do not configure the nodes; just add them.

The main router DHCP server will assign IPs from its IP pool. If you set manually-assigned IPs in the router per client MAC, set these from within the same DHCP server pool. If you set client-side static IPs on a client, set these outside the router DHCP server pool.

Only have one DHCP server on the network.

And don't depend on the client list... if it's wonky, reset w/Initialize the router from within the webUI. I'd do this anyway for a clean install.

Note that if you remove a node from the AiMesh, it is reset automatically.

OE
 
Last edited:
I can't say I follow all of this. Something is likely not setup right.

Reset all routers before configuring the network. Do not configure the nodes; just add them.

The main router DHCP server will assign IPs from its IP pool. If you set manually-assigned IPs in the router per client MAC, set these from within the same DHCP server pool. If you set client-side static IPs on a client, set these outside the router DHCP server pool.

Only have one DHCP server on the network.

And don't depend on the client list... if it's wonky, reset w/Initialize the router from within the webUI. I'd do this anyway for clean install.

OE

Every routers have been reset... and multiple times (it has to be reset to join the mesh)

I have even made 2 mesh to test in turn ([Blue Cave -> 68U] and [68U -> 68U]), all have the same DHCP pool.
With 68U as router, all devices that have manual IP got their IPs from the manual pool regardless connected to router or node.
With Blue Cave as router, devices connected to the Blue Cave got IP from the manual pool, devices connected wired or wireless to the node got dynamic IP

Attached a cap of same devices showing up twice, one manual IP, one dynamic (the one with higher transfer rate was current, the other one was not active (since I couldn't connect to that IP))
 

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Every routers have been reset... and multiple times (it was reset

I have even made 2 mesh to test in turn ([Blue Cave -> 68U] and [68U -> 68U]), all have the same DHCP pool.
With 68U as router, all devices that have manual IP got their IPs from the manual pool regardless connected to router or node.
With Blue Cave as router, devices connected to the Blue Cave got IP from the manual pool, devices connected wired or wireless to the node got dynamic IP

Attached a cap of same devices showing up twice, one manual IP, one dynamic (the one with higher transfer rate was current, the other one was not active (since I couldn't connect to that IP))

What is a manual IP pool?

That pic shows two clients; each has one IP address; the front doorbell has a poor signal. All normal except most people use 192.168.1.*

OE
 
What is a manual IP pool?

That pic shows two clients; each has one IP address; the front doorbell has a poor signal. All normal except most people use 192.168.1.*

OE

I mean the manual assigned IP table in DHCP setup.

They are the same device.
9C:8E:CD:25:DB:B3 is the actual MAC and 192.168.74.53 is the IP in the assigned table.
DA:50:E6:25:DB:B3 is the modified MAC when connected to a node, dynamic pool starts from 74.100

DA:50:E6 is the same for all devices connected the same node (this prefix changes when node is turned off and on and reconnects to the router)
Attached another cap of a canon printer connected to the same node which has the same MAC prefix.
 

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I mean the manual assigned IP table in DHCP setup.

They are the same device.
9C:8E:CD:25:DB:B3 is the actual MAC and 192.168.74.53 is the IP in the assigned table.
DA:50:E6:25:DB:B3 is the modified MAC when connected to a node, dynamic pool starts from 74.100

DA:50:E6 is the same for all devices connected the same node (this prefix changes when node is turned off and on and reconnects to the router)
Attached another cap of a canon printer connected to the same node which has the same MAC prefix.

I see now... duplicate client entries with phantom/non-vendor MACs.

Is the node wired to the Blue Cave?

Try reflashing the Blue Cave; else downgrading its firmware?

What was wrong with the 3x68U AiMesh?

OE
 
I see now... duplicate client entries with phantom/non-vendor MACs.

Is the node wired to the Blue Cave?

Try reflashing the Blue Cave; else downgrading its firmware?

What was wrong with the 3x68U AiMesh?

OE

All router and nodes are connected wirelessly for now, but don't think that's the cause as using 68U as router has no DHCP problem.
The house, just moved in a few months ago, is not wired yet, planning to do so in a few weeks. That's the reason I'm preparing for that.

The cable modem, so the router, are on the side wall of the family room hiding behind the TV.
I'm moving the router to the wall on the other side, so it's at the center line of my house and also more inline with other nodes.
It will be on a decorative shelf and the 3-horn 68U monster certainly do not look good, so thinking the Blue Cave is a nice centerpiece :)

Also the 3x68U do occasionally have node disconnection as I've seen from people's comment, in fact, during the brief time using Blue Cave as the router, I didn't see that problem.
 
Gave it last try before returning it.
Downgraded it to older firmware (4/2019) but it has the same DHCP assigned IP issue when running AiMesh main router.

Also, I have been running Blue Cave as AiMesh node since last time and found out the same issue can also happen if it's running as AiMesh node.
If Blue Cave is sitting between main router and another node (A), Node A might be connecting the Blue Cave rather than connecting to the main router in the mesh network.
Any devices connected to the Node A will see a modified MAC address in the main router because they are routing through Blue Cave and they will not get the correct manual assigned IP from DHCP.
 

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