how to findout ip address of PC's connected on particular switch?

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Sep 2nd, 2009

how to findout ip address of PC's connected on particular switch?

I have this problem too.
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Peter Paluch Wed, 09/02/2009 - 23:49

Hello,

By configuring a SPAN port and sniffing all traffic :-)

Seriously, though - a normal switch does not engage in IP communication with the connected stations. It is concerned with their MAC addresses but without any additional requirements, it will not look into the frame contents and try to look for IP addresses (provided it has such functionality because a switch by definition is a Layer2 device).

The DHCP snooping can be used to monitor which stations have request an IP address from DHCP and on which ports they are located. Note, however, that other stations with statically assigned IP addresses will not show in the DHCP snooping database.

There can be other mechanisms to discover the IP addresses of stations connected to a switch and I am would welcome if somebody here will suggest another way to do it but note that a Layer2 switch basically does not have anything to do with IP addresses and you cannot expect it in general to help you discover them.

Best regards,

Peter

ktwaddell Thu, 09/03/2009 - 00:05

Hi

Assuming you know what switchport the pc is on, get the mac-addraess from the cam table for that switchport (if you don't already know it from the pc itself), also note the vlan that switchport is in, goto the vlan gateway and look in the arp table for ip address that is connected that mac-address, it takes only minutes that way.

Thanks

Kev

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