From: Deep Ratan (deep.ratan@gmail.com)
Date: Fri Sep 30 2005 - 12:26:26 GMT-3
John,
Your reply answers my question. I didn't know layer-2 information is
propagated via VTP across the entire VLAN domain.
In reiteration: If I do a "show cam dyn" on a switch, I'll see the mac
address of an end user machine that is connected 10 switches away, assuming
both switches have the same VLAN, VTP is working, etc?
On 9/30/05, Sheahan, John <John.Sheahan@priceline.com> wrote:
>
> "sh cam dyn" will show you all mac addresses that the switch knows about
> from a layer two persective. That includes machines plugged into hubs
> that are plugged into switch. It will also know about mac addresses on
> other switches that are trunked to the switch.
>
> If you are running IOS, you can easily sort through 10,000 mac addresses
> with the following command:
>
> "sh mac-address-table | begin 0009.b7e0.c2e"
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> Deep Ratan
> Sent: Friday, September 30, 2005 11:04 AM
> To: ccielab@groupstudy.com
> Subject: Re: layer-2 interview question
>
> does "show cam" display mac address of A) machines directly connected to
> the
> switch ports of the switch or B) machines on all vlans across all
> switches
> in those vlans?
>
> If B) is true, the output of that command could have 10,000 entries.
>
> On 9/30/05, Adam S. Roth <adam@therothfamily.net> wrote:
> >
> > Show cam
> >
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> >
> >
> >
> >
> > -----Original Message-----
> > From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
> Of
> > Deep
> > Ratan
> > Sent: Friday, September 30, 2005 10:48 AM
> > To: ccielab@groupstudy.com
> > Subject: layer-2 interview question
> >
> >
> > Hi Everyone,
> > Sorry to ask a networking-101 question but being a WAN guy, I haven't
> been
> > working with switches in the past few years. An interviewer asked me
> this
> > question, "If I give you a MAC address that is causing a broadcast
> storm,
> > how will you locate the culprit in a switched environment that has
> several
> > dozen switches and routers?"
> >
> > I replied, "You'll need to give me a layer-3 address so I can trace it
> to
> > the right switch/router and then look up the ARP table to see on what
> port
> > the offending machine lives" The interviewer didn't like the answer.
> In
> > retrospect, I should probably have said, "A broadcast storm renders
> the
> > network unusable, so I'll start with looking at my network management
> > station to see what LAN segment is giving off a critical alarm"
> >
> > Anyway, my question to members of groupstudy is this: In an
> environment
> > with
> > several dozen switches, if you're given just a MAC address, can you
> find
> > out
> > where the machine lives?
> >
> > thanks, Deep
> >
> >
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