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Forum Replies

  1. Hi Fabian,

    When you configure a VLAN as the primary VLAN then it will be primary. It can’t be the primary and “regular” VLAN at the same time. When you want to migrate to a private VLAN…do it when nobody is around, it’s easy to break stuff :slight_smile:

    Do you want to use private VLANs to prevent server-to-server traffic? If so, I would configure a new VLAN as the primary VLAN with some new secondary VLANs. Assign some unused switchports to it, see if it works. Configure the interface that connects to the firewall as the promiscuous port. When it works, you can assign the s

    ... Continue reading in our forum

  2. do we have to run (switchport access vlan ##) on community or isolated ports?

  3. Hello Azm

    Yes, it is possible to configure multiple trunk ports as promiscuous ports for a single primary VLAN. You would configure this if you want to span a primary VLAN over three switches for example.

    Secondly, it is possible as well to configure a single trunk port as a promiscuous port for multiple primary VLANs. This again, would be the case if you have multiple primary VLANs that you want to span over more than one switch. Specifically, Cisco states:

    Multiple private VLAN pairs can be specified using the switchport private-vlan mapping trunk command

    ... Continue reading in our forum

  4. Hello Laz,
    Very nice explanation as usual. Thank you so much.


  5. Hello Edi

    The configuration on the interfaces connecting SW1 and SW2 are configured as trunks that include VLANs 500 501 and 502. Although we are not told in Rene’s diagram which interface this connection is on, let’s assume that it’s Fa0/5. The configuration for these interfaces can be seen below:

    **Switch 1**

    interface fastethernet 0/5
     switchport mode trunk
     switchport trunk allowed vlans 500,501,502

    **Switch 2**

    interface fastethernet 0/5
     switchport mode trunk
     switchport trunk allowed vlans 500,501,502

    I hope this has been helpful!


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