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  • 1.  CX 6100 Switch no DHCP with untagged Ports

    Posted Oct 29, 2021 09:36 AM
    Hallo,

    I just set up a switch (6100) through Central. The ports for the clients are set up as follows:

    interface 1/1/1
    no shutdown
    vlan trunk native 110
    vlan trunk allowed 130

    But now the devices here do not get assigned DHCP addresses. If I set up the port as vlan access 110, the devices get an IP assigned.
    The devices get their IP addresses from our router. The following route is set up to this:

    ip route 0.0.0.0/0 172.20.120.254

    Best regards

    ------------------------------
    Tim Stebel
    ------------------------------


  • 2.  RE: CX 6100 Switch no DHCP with untagged Ports

    Posted Oct 29, 2021 10:24 AM
    Edited by TA18 Oct 29, 2021 10:24 AM

    Hello Tim,

    why do you have a trunk configuration on your client ports? What type of devices do you have there? Most clients(laptops, PCs, printers etc.) don't understand the concept of vlan tagging and will send the traffic untagged(with no vlan tag). Which with your configuration the switch will understand as vlan 110(your native vlan).
    Or do you have APs connected on these client ports?

    Anyway a quick thought about this if you check the output of show interface 1/1/1 do you see

    Native VLAN: 110
    Allowed VLAN List: 130
    or 
    Native VLAN: 110
    Allowed VLAN List: 110,130

    Maybe 110 is not in the allowed vlan list for the respective interface.

    HTH



    ------------------------------
    Toni Andreev
    ------------------------------

    Original Message


  • 3.  RE: CX 6100 Switch no DHCP with untagged Ports

    Posted Oct 29, 2021 10:46 AM
    Thanks for your feedback! Our phones use the 130 voice vlan and the clients go to the 110 vlan. 
    This is my Output:

    Native VLAN: 110
    Allowed VLAN List: 130

    So it is due to the missing allowed vlan. We will set it up and test. Thanks a lot!

    ------------------------------
    Tim
    ------------------------------

    Original Message


  • 4.  RE: CX 6100 Switch no DHCP with untagged Ports

    Posted Oct 29, 2021 11:58 AM
    Hi Tim,

    Toni is correct here and vlan 110 is missing for your interface configuration.
    The allowed/available VLANs on a trunk are the VLANs listed under the "allowed" list only and defining the native VLAN is not explicitly allowing it on the trunk. So in your case you have to add vlan 110 under the allowed list. 

    ------------------------------
    Stanislav Naydenov
    ------------------------------

    Original Message


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