Core Switch Migration..

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Feb 27th, 2012
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Hi ,

I'am doing a core swith migration 4506. I need to find out the servers attached to my core switch,

the problem is some time I'am getting the ip address and some time ip address is not comming, I'am doing this with this command,

Switch # sh mac-address interface fastethernet 0/1

I'am gettting the mac address, but when I'am trying to find the IP address nothing is comming up.

Switch# sh arp | include <Mac- Address>

can any one please help on this

and my other question is when do we confugure native vlan and native trunk port

Thanks for all your help in advance.

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fb_webuser Mon, 02/27/2012 - 06:39
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The ip address would only be in the switches ARP table if the switch tried to communicate with the server/host or routed a packet to that host (in the case of a layer 3 switch). You can ping to the broadcast address to get all hosts entered in the arp table but they will timeout after 30s IIRC something small anyway


Posted by WebUser Stuart Gall

Gurpreet Kochar Mon, 02/27/2012 - 10:39
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To answer the second question

Native vlan is a vlan which is untagged.

Generally you do not need to configure native vlan but following is one of the scenarios when you would need to configure native vlan trunk port


native vlan10            native vlan 1(default)

If above is the situation; then on switch B you will need the following command

switchport trunk native vlan 10

Or vice versa on switch-A

The idea here is to keep the untagged traffic in same vlan on both the switches so that vlan leaking does not occur

zoltanszasz Mon, 03/26/2012 - 17:11
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why not map and document network with Lansurveyor or cisco LMS?


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