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show mac address-table / show mac-address-table

Mar 22, 2013 10:25 AM

MartynJ 14 posts since
Oct 30, 2009

Hi all,

 

I have the Wendell Odom study books for INCD1 & 2, and have seen the show mac address table command in two formats.

 

show mac-address-table

 

&

 

show mac address-table

 

I also have the Cisco Press CCNA Flashcards book also, and that only mentions the first command above.

 

I have seen in a simulator of a 2960 'WS-C2960-24TT', IOS 12.2(25r), that only the first option is available, and the other errors.

 

However at work we use 2007 build 'WS-C2960G-48TC-L' switches, IOS 12.2(40)SE, which only accept the second of the two commands above, the first command errors.

 

It may seem trivial, but I want to sudy and get it right, so I am interested in anyone's thoughts or experiences with this.

 

Thanks,

Martyn

  • Scott Morris - CCDE/4xCCIE/2xJNCIE 8,395 posts since
    Oct 7, 2008
    Currently Being Moderated
    1. Dec 17, 2009 10:46 AM (in response to MartynJ)
    Re: show mac address-table / show mac-address-table

    My 3560 only has the second itteration.

     

    INE-SW1#show mac?
    mac

     

    INE-SW1#show mac ?
      access-group   MAC access-group
      address-table  MAC forwarding table

     

    INE-SW1#show mac ad
    INE-SW1#show mac address-table ?
      address       Address to lookup in the table
      aging-time    MAC address table aging parameters
      count         Number of MAC addresses in the table
      dynamic       List dynamic MAC addresses
      interface     List MAC adresses on a specific interface
      learning      Display learning on VLAN or interface
      move          MAC Move information
      multicast     List multicast MAC addresses
      notification  MAC notification parameters and history table
      secure        List secure MAC addresses
      static        List static MAC addresses
      vlan          List MAC addresses on a specific vlan
      |             Output modifiers
      <cr>

     

    INE-SW1#show mac address-table
              Mac Address Table
    -------------------------------------------

     

    Vlan    Mac Address       Type        Ports
    ----    -----------       --------    -----
    All    0100.0ccc.cccc    STATIC      CPU
    All    0100.0ccc.cccd    STATIC      CPU
    All    0180.c200.0000    STATIC      CPU
    All    0180.c200.0001    STATIC      CPU
    All    0180.c200.0002    STATIC      CPU
    All    0180.c200.0003    STATIC      CPU
    All    0180.c200.0004    STATIC      CPU
    All    0180.c200.0005    STATIC      CPU
    All    0180.c200.0006    STATIC      CPU
    All    0180.c200.0007    STATIC      CPU
    All    0180.c200.0008    STATIC      CPU
    All    0180.c200.0009    STATIC      CPU
    All    0180.c200.000a    STATIC      CPU
    All    0180.c200.000b    STATIC      CPU
    All    0180.c200.000c    STATIC      CPU
    All    0180.c200.000d    STATIC      CPU
    All    0180.c200.000e    STATIC      CPU
    All    0180.c200.000f    STATIC      CPU
    All    0180.c200.0010    STATIC      CPU
    All    ffff.ffff.ffff    STATIC      CPU
       1    000a.b82d.10e0    DYNAMIC     Fa0/16
       1    0012.80b6.4cd8    DYNAMIC     Fa0/3
       1    0012.80b6.4cd9    DYNAMIC     Fa0/16
       1    0014.6915.4100    DYNAMIC     Fa0/16
       1    0018.b921.9200    DYNAMIC     Fa0/16
       1    0018.b921.9278    DYNAMIC     Fa0/1
       1    0018.b974.528f    DYNAMIC     Fa0/16
       1    0019.0617.660f    DYNAMIC     Fa0/13
       1    0019.0617.6610    DYNAMIC     Fa0/14
       1    0019.0617.6611    DYNAMIC     Fa0/15
       1    001b.d450.970f    DYNAMIC     Fa0/19
       1    001b.d450.9710    DYNAMIC     Fa0/20
       1    001b.d450.9711    DYNAMIC     Fa0/21
       4    0018.b974.528f    DYNAMIC     Fa0/16
      45    0018.b945.d5a9    DYNAMIC     Fa0/19
      45    0018.b945.f780    DYNAMIC     Fa0/5
      45    0018.b974.528f    DYNAMIC     Fa0/16
      56    0018.b945.f781    DYNAMIC     Fa0/16
      56    0018.b974.528f    DYNAMIC     Fa0/16
      56    0019.069c.80e1    DYNAMIC     Fa0/19
       6    0018.b974.528f    DYNAMIC     Fa0/16
       6    0019.069c.80e0    DYNAMIC     Fa0/13
    Total Mac Addresses for this criterion: 42
    INE-SW1#

     

    Scott

  • Chris Buscemi 203 posts since
    Mar 16, 2009
    Currently Being Moderated
    2. Dec 17, 2009 1:42 PM (in response to MartynJ)
    Re: show mac address-table / show mac-address-table

    I can understand the importance to you of "getting it right" but I think the important thing for you to remember is the command you're trying to get to.

     

    You know ultimately that you need mac, address, and table in your command to get the results you want. As you can see the "?" worked very well in Scott's demonstration to show what his choices were as he went along. And I'll bet you, even in all of his CCIE greatness, he doesn't only use the "?" when he's helping out someone studying for the CCENT.

     

    When you are making your way through and you want to make sure you use the right context in your commands, don't be afraid to use the "?" key. That way you'll be sure to always find the command you are looking for.

     

    The biggest part is knowing which command you're looking for, and in this particular example, you've shown you do.

     

     

    Hope that helps.

     

     

     

    Chris

  • Scott Morris - CCDE/4xCCIE/2xJNCIE 8,395 posts since
    Oct 7, 2008

    heheheh...   I do use the ? key a lot, mostly because I don't memorize commands!  If I do, Cisco goes and changes things around and just irritates me. 

     

    Never be afraid of asking for a little help!

     

    Scott

  • jt101 4 posts since
    Nov 25, 2009

    Scott showed an example that resembles the output of my 2960 switches.  I would like to know what is the purpose of the mac addresses that are bound to the CPU in the mac address table, and why are there so many?  In my switch there are 20 addresses that are statically bound to the CPU, and one of them is the broadcast address.  Notice that these addresses are present even when I have not statically assigned any addresses to any interfaces, and I have no computers connected to the switch to learn the addresses automatically.  I would really like to understand why they exist?

     

    Switch#sh mac-address-table
              Mac Address Table
    -------------------------------------------

     

    Vlan    Mac Address       Type        Ports
    ----    -----------       --------    -----
    All    0100.0ccc.cccc    STATIC      CPU
    All    0100.0ccc.cccd    STATIC      CPU
    All    0180.c200.0000    STATIC      CPU
    All    0180.c200.0001    STATIC      CPU
    All    0180.c200.0002    STATIC      CPU
    All    0180.c200.0003    STATIC      CPU
    All    0180.c200.0004    STATIC      CPU
    All    0180.c200.0005    STATIC      CPU
    All    0180.c200.0006    STATIC      CPU
    All    0180.c200.0007    STATIC      CPU
    All    0180.c200.0008    STATIC      CPU
    All    0180.c200.0009    STATIC      CPU
    All    0180.c200.000a    STATIC      CPU
    All    0180.c200.000b    STATIC      CPU
    All    0180.c200.000c    STATIC      CPU
    All    0180.c200.000d    STATIC      CPU
    All    0180.c200.000e    STATIC      CPU
    All    0180.c200.000f    STATIC      CPU
    All    0180.c200.0010    STATIC      CPU
    All    ffff.ffff.ffff    STATIC      CPU
    Total Mac Addresses for this criterion: 20
    Switch#

  • John 2,289 posts since
    Jan 17, 2009
    Currently Being Moderated
    6. Feb 6, 2010 8:27 PM (in response to MartynJ)
    Re: show mac address-table / show mac-address-table

    Hi Martyn

     

    I also noticed that in study materiels and i think i posted here about it.

     

    I am assuming that in an exam you could use the question mark or if it is just a question and not a simulator then it does not matter if they have a hypen or not.

     

    In the real world like Scott pointed out just use the ?

     

     

     

     

     

    John

  • Cain 1 posts since
    Mar 26, 2011

    Hi Scott

    A quick question for you.  Fa 0/16 come up quite a bit on the mac table with different mac addresses.  Would that just be from multple PCs plugging into that port or is something else causing that?  Please let me know

    Thanks

    Cain

     

     

      1    000a.b82d.10e0    DYNAMIC     Fa0/16

       1    0012.80b6.4cd8    DYNAMIC     Fa0/3

       1    0012.80b6.4cd9    DYNAMIC     Fa0/16

       1    0014.6915.4100    DYNAMIC     Fa0/16

       1    0018.b921.9200    DYNAMIC     Fa0/16

       1    0018.b921.9278    DYNAMIC     Fa0/1

       1    0018.b974.528f    DYNAMIC     Fa0/16

       1    0019.0617.660f    DYNAMIC     Fa0/13

       1    0019.0617.6610    DYNAMIC     Fa0/14

       1    0019.0617.6611    DYNAMIC     Fa0/15

       1    001b.d450.970f    DYNAMIC     Fa0/19

       1    001b.d450.9710    DYNAMIC     Fa0/20

       1    001b.d450.9711    DYNAMIC     Fa0/21

       4    0018.b974.528f    DYNAMIC     Fa0/16

      45    0018.b945.d5a9    DYNAMIC     Fa0/19

      45    0018.b945.f780    DYNAMIC     Fa0/5

      45    0018.b974.528f    DYNAMIC     Fa0/16

      56    0018.b945.f781    DYNAMIC     Fa0/16

      56    0018.b974.528f    DYNAMIC     Fa0/16

      56    0019.069c.80e1    DYNAMIC     Fa0/19

       6    0018.b974.528f    DYNAMIC     Fa0/16

       6    0019.069c.80e0    DYNAMIC     Fa0/13

  • Ajay 9 posts since
    Oct 23, 2010
    Currently Being Moderated
    8. Jul 3, 2011 12:00 PM (in response to Cain)
    Re: show mac address-table / show mac-address-table

    I belive this could be due to a Hub or a non cisco switch connected with many PC's connected to it.

     

    Regards

    Aj

  • Scott Morris - CCDE/4xCCIE/2xJNCIE 8,395 posts since
    Oct 7, 2008
    Currently Being Moderated
    9. Jul 3, 2011 12:51 PM (in response to Ajay)
    Re: show mac address-table / show mac-address-table

    Or a trunk to another switch.   Either would be correct.  but it's clearly a link to another part of your network.

     

    Scott

  • Florin Bârhală 6 posts since
    Feb 10, 2009
    Currently Being Moderated
    10. Mar 29, 2012 3:02 PM (in response to John)
    Re: show mac address-table / show mac-address-table

    Hi guys,

     

    I found this question and it's really bugging me out:

     

    "

    I would like to know what is the purpose of the mac addresses that are bound to the CPU in the mac address table, and why are there so many? In my switch there are 20 addresses that are statically bound to the CPU, and one of them is the broadcast address. Notice that these addresses are present even when I have not statically assigned any addresses to any interfaces, and I have no computers connected to the switch to learn the addresses automatically. I would really like to understand why they exist?

     

    Switch#sh mac-address-table
    Mac Address Table
    -------------------------------------------

     

    Vlan Mac Address Type Ports
    ---- ----------- -------- -----
    All 0100.0ccc.cccc STATIC CPU
    All 0100.0ccc.cccd STATIC CPU
    All 0180.c200.0000 STATIC CPU
    All 0180.c200.0001 STATIC CPU
    All 0180.c200.0002 STATIC CPU
    All 0180.c200.0003 STATIC CPU
    All 0180.c200.0004 STATIC CPU
    All 0180.c200.0005 STATIC CPU
    All 0180.c200.0006 STATIC CPU
    All 0180.c200.0007 STATIC CPU
    All 0180.c200.0008 STATIC CPU
    All 0180.c200.0009 STATIC CPU
    All 0180.c200.000a STATIC CPU
    All 0180.c200.000b STATIC CPU
    All 0180.c200.000c STATIC CPU
    All 0180.c200.000d STATIC CPU
    All 0180.c200.000e STATIC CPU
    All 0180.c200.000f STATIC CPU
    All 0180.c200.0010 STATIC CPU
    All ffff.ffff.ffff STATIC CPU
    Total Mac Addresses for this criterion: 20"

     

    Any ideas/answers to it?

  • mjones - CCNP 196 posts since
    Aug 1, 2010

    Wow - I started this thread back in 2009!  Just browsing and saw it has been bumped.

     

    Florin, in another thread regarding your question: https://learningnetwork.cisco.com/thread/10473  Conwyn gives the answer below:

     

    CDP  UDLD/DTP/VTP/Pagp= 0100.0ccc.cccc 

    CGMP =  0100.0ccc.cccd 

    system-cpp-bpdu-range  = 0180.C200.0000 - 0180.C200.000F

    GARP = 0180.C200.0020 - 0180.C200.002F

     

    So these 20 mac addresses are used for processes such as CDP, VTP, DTP etc.

     

    Hope this helps,

    MJ

  • Florin Bârhală 6 posts since
    Feb 10, 2009

    Hi mate,

     

    Thank you for your kind answer!

  • Scott 1 posts since
    May 25, 2011
    Currently Being Moderated
    13. Jul 19, 2012 10:58 AM (in response to MartynJ)
    Re: show mac address-table / show mac-address-table

    From the CCNP SWITCH official certification guide:

     

    mac-address-table was used until Catalyst IOS ver 12.1(11)EA1

    mac address-table is used in more recent versions.

     

    However, the 4500 and 6500 continue to use mac-address-table.

    Also, many switch platforms support either syntax.

  • Shailini 16 posts since
    Dec 5, 2011
    Currently Being Moderated
    14. Aug 16, 2012 9:14 AM (in response to Scott)
    Re: show mac address-table / show mac-address-table

    Hi, I wonder  about  maximum no. of entries that mac address-table allows.

    I came accross in the book that if there's a new entry and mac address-table is full, it will remove the oldest one in basis  of their inactivity timer.

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