Turning a Catalyst 2960 into a semi dumb switch

Posted on 2009-02-16
Last Modified: 2012-06-27
I need to take a C2950 and turn it into a semi dumb switch.  I say that because, I want two segments on it, but i do not want the switch to broad cast that info.

Here is the scenario.

In my lab i have a switch, it has multiple segments on it.  One of my segments will be connected to my "external" (company) network.  the other will be connected to devices on a private subnet.  The goal is to be able to move the external segments uplink to any switch port on my corp network and have it simply act as a dumb switch.

Pointers \ check list of things i need to make sure to disable would be great. If this were a more permanent project, i would go thru the trouble of putting in the CRs have the corp switch trunked down, but this is a rapidly evolving project and dont have the time for that kind of overhead.

Question by:mooreja557
    LVL 18

    Expert Comment

    by:Don S.
    Turn off routing and create two Vlans.  Set vlan 1 to be untagged on which ever ports you want, and vlan2 untagged on the other ports.  The two vlans will stay seperate and the untagged directive means that whatever you plug into that port just goes to that vlan.

    Author Comment

    thank you but that doesnt address the issue of things like STP.  I have already endabled bpdufilter, but have not tested it yet. (never had to use it before).
    LVL 50

    Expert Comment

    by:Don Johnston
    What is YOUR definition of a "dumb" switch?

    As far as switches go, the 2960 is already pretty low on the IQ scale. :-)

    Create the VLAN's, disable trunking and put the ports in the VLAN you want them in. That's as simple as it gets.

    Author Comment

    i consider a dumb switch an unmanaged switch.

    ill check my current config in the morning and get back to you.
    LVL 50

    Expert Comment

    by:Don Johnston
    Me too.

    So here's what you need to do.

    conf t
    vlan 10
    vlan 20
    int range f0/1 -12
     switchport mode access
     switchport access vlan 10
    int range f0/13 -24
     switchport mode access
     switchport access vlan 20

    Open in new window


    Author Comment

    i want to say that i tried that and the corp switches killed it, but it could have been my monday morning stupidity... ill try again in the am, and see if the port gets killed.

    thanks for your help, will keep u posted.

    LVL 50

    Accepted Solution

    "the corp switches killed it"

    It could be they're checking for BPDU's. If that's the case then do the following on the port that connects to corporate:

    int fa0/1
     spanning-tree portfast
     spanning-tree bpdufilter enable

    Open in new window


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