Cisco Switch IOS Command To Show MAC-to-IP Address Table

On a Cisco 3750 Catalyst switch what would be the command (or commands) to display the MAC Address to IP Address table mappings ?  At a site it needs to be determined, based on a particular IP address, what the associated MAC address is.  Also, is there some way from that command or another command to determine what interface that traffic is originating from ?  TIA ...
LGroup1Asked:
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JonathanSpitfireSenior Solutions EngineerCommented:
These commands are fairly universal on just about any Cisco IOS device made within the last 15 years:

show arp (or "sh arp") will give you the ARP table:

Protocol  Address          Age (min)  Hardware Addr   Type   Interface
Internet  10.32.53.66             27   b6b4.767f.c4d7  ARPA   Vlan311
Internet  10.32.53.64              4   80b4.0b69.9f31  ARPA   Vlan311
Internet  10.32.52.64             22   a044.1cdb.5cdb  ARPA   Vlan310
Internet  10.32.53.65            178   2010.7a05.951e  ARPA   Vlan311
Internet  10.32.53.70              1   b63a.4b14.8a46  ARPA   Vlan311

"sh mac address-table" will give you the MAC address of all active devices and what port that MAC address is connected to:

          Mac Address Table
-------------------------------------------

Vlan    Mac Address       Type        Ports
----    -----------       --------    -----
 300    0002.b7c9.5355    DYNAMIC     Fa1/0/33
 300    000c.bb39.53cb    DYNAMIC     Gi1/0/2
 300    0019.b79c.3d98    DYNAMIC     Fa1/0/14
 300    00c0.e348.9cb8    DYNAMIC     Fa1/0/19
 310    0003.f2e1.dfe6    DYNAMIC     Gi2/0/4
 310    0004.f2e8.73f5    DYNAMIC     Gi3/0/5
 310    a044.1cdb.5cdb    DYNAMIC     Gi3/0/15

In the example above, you can see that IP address 10.32.52.64 corresponds to MAC address a044.1cdb.5cdb, which is on vlan 310 and connected to physical port Gigabit Ethernet 15 on switch stack 3 (3/0/15 - the first digit is 3 and that tells me that there are at least 3 switches in the stack).

To get information about the stack, just type, "show switch"

Hope this helps!

Jonathan
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LGroup1Author Commented:
Perfect, thanks !
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LGroup1Author Commented:
This is perfect, thanks !
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