Dynamicly building a mac address table for a certain port on a switch.

Discussion in 'Networking, Telephony & Internet' started by ausghostdog, Aug 19, 2013.

  1. BAK

    BAK Member

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    Seems fine aside from "We then add VLAN 40 is added" grammatical error. Did this come with a network diagram?
     
  2. evilasdeath

    evilasdeath Member

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    It worries me that you think you need to know the IP address of the server before you can find out the mac-address.

    Additionally i'm not quite sure what you are meant to learn out of the problem, and that your rules are that you can't change anything yet you want to unplug the switch links.
     
  3. FiShy

    FiShy Member

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    This is the worst part, its a loaded question with a poor outcome.

    Doing somthing like this in the real world would get you shown the door.
     
  4. OP
    OP
    ausghostdog

    ausghostdog Member

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    Well, no I knew the mac address that;s the easy part. The part I was having issue with was adding the mac address to the table of the switch dynamicly.

    It wasn't until this morning I found out we could add an ip address to the system for it to work.

    If I could add the mac address manually to the mac table for the switch I would have but it had to be dynamic.
     
  5. evilasdeath

    evilasdeath Member

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    Port security does not add the mac-addresses to the CAM table,

    I don't think there is even a method to statically add mac-addresses to the CAM table it is entirely a dynamic process and one you don't want to mess with since it works so well, and SPT in particular relies on the ability to dynamically overwrite the CAM table as required.

    There are very few situations where port security should be used, this isn't one of them.
     
  6. OP
    OP
    ausghostdog

    ausghostdog Member

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    That's why I asked if it;s even possible to do it without the ip address, as it turns out it;s not.
     
  7. evilasdeath

    evilasdeath Member

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    Why do you keep coming back to the IP address, it has nothing to do with the CAM table.

    The CAM table has nothing to do with the IP address, with some protocols you don't even use a IP at all.
     
  8. OP
    OP
    ausghostdog

    ausghostdog Member

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    Ok, explain to me how to add mac address to a cam table dynamicly.
     
  9. evilasdeath

    evilasdeath Member

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    go read your textbook and understand layer 2 learning and forwarding and come back and come back and try and explain it.
     
  10. OP
    OP
    ausghostdog

    ausghostdog Member

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    If I connect a system A to a switch A, and then switch A to switch B, switch b will not learn the mac address of system a if there is no communication going on.

    There needs to be a packet sent from system a to switch b for it to learn the mac address.

    How do I send a pack from system a to switch b, if nothing has an ip address, there is nothing else going on in the system other than default stp settings?
     
  11. Heywood

    Heywood Member

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    Switches at least in the traditional sense work with frames, not packets
     
  12. evilasdeath

    evilasdeath Member

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    The device could send out a DHCP request

    The device might be using netbuei/netbios

    The device might be using clns

    I could be using a tester generating pure layer 2 traffic.

    yes traffic is required, but the MAC layer is independent on the IP layer.
     
  13. OP
    OP
    ausghostdog

    ausghostdog Member

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    I'm working off the system I have in front of me, and that's all I am focusing on, there is no dhcp server, when I say every thing is default I mean everything. nothing has a setting.

    The network we were given to work on is shitty, I'll agree with anyone on that, who designes a network with no ip address and yes lay 2 deals only with mac address.
     
  14. evilasdeath

    evilasdeath Member

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    I design services for customers all the time without any customer IP address's

    Sure i have IP address's on the switches to log into them, but end to end it is just a VLAN no layer 3 at all.
     
  15. ic3solo

    ic3solo Member

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    Thought about Private VLANs? :)
     
  16. Heywood

    Heywood Member

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    The OP is using the 2960 platform which doesn't actually support private VLANs

    However there is a similar capability using switchport protected which is creating isolated ports of local switch significance and I'm not sure it would be something that works on trunk ports.
     
  17. itsmydamnation

    itsmydamnation Member

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    layer 2 can and does deal with way more then mac address. This is why i hate networking, people get taught wrong then they don't know how to apply there knowledge to other things because they are looking at it from the wrong perspective. Layer 2 at a minimum provides next device reachability. People might see this as semantics, but it isn't.

    If you want to dynamically learn mac addresses use a protocol that can dynamically share mac address. that being TRILL/fabric path. Otherwise the CAM table is built off received traffic or statically configured with the egress interface. I wouldn't really call standard mac based learning dynamic, in most instances it only learns the egress interface after it needs to know. its worth noting that depending on equipment and protocols there is more then one way to learn an Ethernet mac address.
     
  18. OP
    OP
    ausghostdog

    ausghostdog Member

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    All good guys, as I stated a few post back I just added the ip address once I got confirmation for the lecturer.
     

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