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[Help Needed] Omada VLAN DHCP Issue

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[Help Needed] Omada VLAN DHCP Issue

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kblikefly

2021-12-22 07:40:39

Posts: 2

Helpful: 0

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Registered: 2021-12-22

[Help Needed] Omada VLAN DHCP Issue

2021-12-22 07:40:39

Model: SG2210MP

Hardware Version: V1

Firmware Version: 1.0.2 Build 20210806 Rel.55686

Hi All,

I am currently experiencing VLAN and DHCP issues.

Here is the simple Topology:

4 VLANs on TL-SG2210MP (Lan, Home, IoT and Guest)

1 Unmanaged TP-LINK switch connect to TL-SG2210MP via MoCA adapters. (Port that the unmanaged switch connect to had been set to All VLANs)

1 AP and 1 PC wire connect to this Unmanaged switch.

Issue:

Even I manually set the fix IP for the PC to get DHCP from "VLAN - Home", it keeps getting the DHCP from "VLAN - Lan".

Looks like the "VLAN - Lan" has a higher priority.

If I manually change the Port that the unmanaged switch connects to "VLAN - Home", the PC will get the correct IP, but if I change back to All VLANs, the PC will get IP from "VLAN - Lan" again.

Any help would be much appreciated. Thank you.

3 Reply

Questionmark

LV3

2021-12-22 17:16:52

Posts: 110

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Registered: 2019-05-09

Re:[Help Needed] Omada VLAN DHCP Issue

2021-12-22 17:16:52

@kblikefly

When your client sends a DHCP request, multiple DHCP servers can respond. Whichever response the client gets first will be the one that it uses. Remember that DHCP works on layer 2 instead of layer 3. You probably don't want to have multiple DHCP servers on the same port that are giving out different IP ranges...

kblikefly

LV1

2021-12-22 18:23:45

Posts: 2

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Solutions: 0

Stories: 0

Registered: 2021-12-22

Re:[Help Needed] Omada VLAN DHCP Issue

2021-12-22 18:23:45

@Questionmark

Thank you so much for the answer.

Is there anything on Omada that it can set which DHCP sever has priority or something. Or it's just totally random?

So even I manually set the PC has fixed IP from the certain DHCP server on the Omada settings, it won't work, right?

Thanks again.

Questionmark wrote

@kblikefly

When your client sends a DHCP request, multiple DHCP servers can respond. Whichever response the client gets first will be the one that it uses. Remember that DHCP works on layer 2 instead of layer 3. You probably don't want to have multiple DHCP servers on the same port that are giving out different IP ranges...

Hank21

2021-12-23 09:32:56

Posts: 3673

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Registered: 2021-12-13

Re:[Help Needed] Omada VLAN DHCP Issue

2021-12-23 09:32:56

Dear @kblikefly ,

kblikefly wrote

Even I manually set the fix IP for the PC to get DHCP from "VLAN - Home", it keeps getting the DHCP from "VLAN - Lan".
Looks like the "VLAN - Lan" has a higher priority.

If I manually change the Port that the unmanaged switch connects to "VLAN - Home", the PC will get the correct IP, but if I change back to All VLANs, the PC will get IP from "VLAN - Lan" again.

The problem is that the switch you have connected behind you is only an unmanaged switch, and when you add it to all VLANs, because although it can forward tagged data, but it cannot set advanced functions such as PVID values, and the PC connected behind it will get the default VLAN's IP.
So you want the PC connected behind the unmanaged switch to get the Home IP address, you can only put it in the HOME VLAN.

Or you can try to get another switch which can support VLAN to replace the unmanaged one.

Best Regards!

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[Help Needed] Omada VLAN DHCP Issue

[Help Needed] Omada VLAN DHCP Issue

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