ARP broadcast on a Cisco switch?

boxerboy1168

Can I send out a broadcast on a switch to collect all the currently connected MAC addresses?? If so what's the command?

Thanks.

I tried Googling it but it's hard to find a direct answer.

Welly_59

The switch will pick up the Mac of connected devices as soon as it receives a packet from that Mac on that interface unless I'm missing something else?

Cisco Inferno

could just ping sweep

boxerboy1168

ok thanks

Cisco Inferno

boxerboy1168 wrote: »

ok thanks

yep, thats what I meant to say, which is sorta the same thing.

One thing to remember is that the default mac address table (CAM Table) lifetime is 5 minutes. Thats why its not too significant.


A host's MAC will not be flushed as long as it continuously sends and receives traffic. If a host has not sent or received any traffic within the duration of the aging time, it's MAC will be removed from the table.


Devices and IPs change and things are moved around. You wouldnt want to wait a while for that to flush.

stlsmoore

I think you can ping the broadcast address and get some hits on a Cisco switch, but it's pretty flaky from my experience. For example pinging 192.168.1.255 on the subnet 192.168.1.0/24.