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New Member

How to find the port of switch base on ip address


Do you someone may give me some guide on how to relocate the port of switch base on I know ip address?Actually this is important when I knew someone computer send out lots of traffic.

bjw Silver

Re: How to find the port of switch base on ip address

If you know the IP address of the suspected device;

1. Go to the default gateway (router/L3 Switch) and do a Show arp with the known IP address.

2. Arp should come back with the MAC address associated with the known IP address.

3. On the subject switch, do a show mac-address (IOS), or show cam static (CatoS). The output of these commands will show you the MAC address and Port/Interface# where that MAC address is being seen.

Hall of Fame Super Blue

Re: How to find the port of switch base on ip address


You don't say whether the switch is layer 2 or layer 3 and whether it is IOS or CatOS.

Assuming IOS.

On the layer 3 device, whether that is the switch itself or a router,

1) show arp | include "ip address" eg

NW-MSQ1-F02-CS1#sh arp | include

Internet 64 000e.d797.1a7f ARPA FastEthernet2/1

2) On the switch

sh mac-address-table address 000e.d797.1a7f

This will give you the port that the switch has registered this mac address against.



New Member

Re: How to find the port of switch base on ip address

Thanks all,I knew now.Thanks you. Here is my step for get port on htat switch.

1.查找高流量的IP 地址

sh ip cache flow

2.根据IP 地址查switch 上的端口


Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to, timeout is 2 seconds:


Success rate is 100 percent (5/5), round-trip min/avg/max = 1/202/1004 ms

sALCNshg01#show arp | include

Internet 0 0011.85ea.2e2d ARPA VLAN100

sALCNshg01#show mac address 0011.85ea.2e2d

Non-static Address Table:

Destination Address Address Type VLAN Destination Port

------------------- ------------ ---- --------------------

0011.85ea.2e2d Dynamic 100 FastEthernet0/41

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