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

    MartynJ
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      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

        • 1. Re: show mac address-table / show mac-address-table
          Scott Morris - CCDE/4xCCIE/2xJNCIE

          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

          • 2. Re: show mac address-table / show mac-address-table
            Chris Buscemi

            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

            • 3. Re: show mac address-table / show mac-address-table
              Scott Morris - CCDE/4xCCIE/2xJNCIE

              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

              • 4. Re: show mac address-table / show mac-address-table
                MartynJ

                Thanks guys,

                 

                Yep, in real life I am a big fan of the ? and tab auto complete (just like Bash shell!).

                 

                I was thinking in terms of the exam, I am sure I will find a way through, just thought its something that could cause a slip up - but being aware of the differences cant hurt at all.

                 

                Thanks again for your replies!

                • 5. Re: show mac address-table / show mac-address-table
                  jt101

                  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#

                  • 6. Re: show mac address-table / show mac-address-table
                    John

                    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

                    • 7. Re: show mac address-table / show mac-address-table
                      Cain

                      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

                      • 8. Re: show mac address-table / show mac-address-table
                        Ajay

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

                         

                        Regards

                        Aj

                        • 9. Re: show mac address-table / show mac-address-table
                          Scott Morris - CCDE/4xCCIE/2xJNCIE

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

                           

                          Scott

                          • 10. Re: show mac address-table / show mac-address-table
                            Florin Bârhală

                            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?

                            • 11. Re: show mac address-table / show mac-address-table
                              mjones - CCNP

                              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

                              • 12. Re: show mac address-table / show mac-address-table
                                Florin Bârhală

                                Hi mate,

                                 

                                Thank you for your kind answer!

                                • 13. Re: show mac address-table / show mac-address-table
                                  Scott

                                  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.

                                  • 14. Re: show mac address-table / show mac-address-table
                                    Shailini

                                    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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