Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Announcements

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

New Member

ARP vs mac-address-table

Hi Guys,

I have one question. In my situation I have directly connected user PC to cisco switch. User is ping able but I do not see any arp entry and I have user MAC is in MAC-table. So how is switch resolving IP to MAC in this case? Why I do not see arp entry, but MAC address is in the table?

Thank you

1 ACCEPTED SOLUTION

Accepted Solutions
Hall of Fame Super Blue

Re: ARP vs mac-address-table

L2 switches usually only record mac-addresses. The only time a L2 switch records an IP to mac-address is when the switch has a management interface with an IP address and you are pinging to that address or from that address.

If you want to see the PC mac to IP mapping, find the PCs default-gateway, go on to that device and look at the arp table.

Jon

6 REPLIES
New Member

Re: ARP vs mac-address-table

From where to where are you pinging? Can you provide what ip addresses you have applied on the devices?

Purple

Re: ARP vs mac-address-table

A switch works at Layer 2 so it doesn't need arp to map L3 address to L2 address for framing.

You are pinging your host from another host or router and the frame is forwarded through the switch with the mac-table.

Regards.

Don't forget to rate helpful posts.
New Member

Re: ARP vs mac-address-table

I am pinging from the switch

New Member

Re: ARP vs mac-address-table

Is the ip address of the switch which is used as source and the end user of the same subnet?


Did you see the arp entry for the switch mac-address in your pc?

Hall of Fame Super Blue

Re: ARP vs mac-address-table

L2 switches usually only record mac-addresses. The only time a L2 switch records an IP to mac-address is when the switch has a management interface with an IP address and you are pinging to that address or from that address.

If you want to see the PC mac to IP mapping, find the PCs default-gateway, go on to that device and look at the arp table.

Jon

New Member

Re: ARP vs mac-address-table

Thank you all, especially Jon

644
Views
0
Helpful
6
Replies