Switch ports ip map

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Jul 26th, 2007
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I have cisco catalyst 3500 XL series 24 ports switch. I need which port connected a device and what is ip and mac address of these devices. Is is possible?

I use show mac-address-table for mac addresses. And i use show arp fro ips. But sometime show arp doesn't work. How can i do this? is it possible???

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Jon Marshall Thu, 07/26/2007 - 03:57
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Which device is doing the Layer 3 routing for the pc's connected to the switch. This is where you need to run the "sh arp"


baranmehmet884 Thu, 07/26/2007 - 04:43
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i know but sh arp doesn't working enough. Sometime i can see a mac address in "show mac-address-table".but i can't find a ip for this mac address in "show arp". what is the reason of this? is it about security settings?

ankbhasi Thu, 07/26/2007 - 05:51
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Hi Friend,

sh arp on switch may not alawys show you ip address for learned mac address because l2 switch is not talking to the machines at IP layer.

Try pinging from switch to that machine and see if that is learned. Or else go to the first L3 hop for machines and try initiating ping from that device to thos emachines and arp entry will be populated.



*Pls rate all helpfull post

baranmehmet884 Thu, 07/26/2007 - 08:30
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Thanks for help! I don't know the devices ips. i want to learn them. And I only have mac addresses. I know i can use shwo arp after ping the ips. But there is so much devices and their ips are dinamyc. So i can't ping over ips. I must find another way. Thanks again.


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