Cisco 851W, switchport command is not recognized.

Posted on 2011-10-28
Last Modified: 2012-05-12
I am a newbie and trying to use switchport command in order to enter switchport mode access. However, switchport command is not recognized in all 4 fastethernet interfaces.

I returned to the privilege mode, and entered:
#show ip interface brief
all four fastethernet ports are all up (nothing is administratively down).

Can anyone please tell me why switchport command is unrecognized?
Question by:Lakemont
    LVL 6

    Expert Comment

    The FastE ports on the 851W are layer3 capable, therefore they are in "switchport" mode by default.

    You should be able to configure access vlan as needed with just switchport access vlan <id> commands on each interface.

    Author Comment

    Then how do I set up these FastEthernet ports so that only end devices with specific mac addresses  can connect to these EastEthernet ports? According to the book, you should first make these ports access by entering
    config-if#switchport mode access
    config-if#switchport port-security maximum [maximum number]
    config-if#switchport port-security violation ....

    However, switchport command is returned as invalid.

    LVL 15

    Accepted Solution

    Actually, the 4 ethernet switch ports on the 851W are layer 2 only and limited in their configurability. It appears they're access mode only for VLAN 1 - this can't be changed so I guess it's ambitious to try and configure for port protection. If it's something you need then you will need to use different hardware.

    Author Comment

    Thank you Frabble.

    I tried to enter switchport command in the VLAN 1, but that command was not recognized either. What does it mean?
    LVL 15

    Assisted Solution

    It means that command is not supported for those interfaces. You may be able to use it on the fast ethernet WAN interface which by default is layer 3 but the options will be limited.
    The 85x series is one of the low end routers and simply isn't capable of what you want to do.

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