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Lets say I have multiple cisco switches that are all on the same VLAN.
The question is:
If I do "arp -a" on a pc that is connected to one of the switches.
Do I get the Ip and Mac addresses of all the pcs on the vlan, or do I get the arp table that is only on the switch that I am connected to?
Lee
Posted 2013-09-30T15:10:50.227
Reputation: 113
ok, so is there a way to get the mac addresses(AND IPS) of all the pcs on the vlan? – Lee – 2013-09-30T15:16:06.007
nmap (filler words) – Gregg Leventhal – 2013-09-30T15:16:51.970
For example if you are on 192.168.1.0/24 you could do nmap -sP 192.168.1.0-255 – Gregg Leventhal – 2013-09-30T15:20:13.393
Thanks, I will look on to it.. But I need to develop it myself. Do you know how they are doing it? It seems by your example that they are just scanning all the ips in the subnet. – Lee – 2013-09-30T15:25:14.917
Yes, that's right. If you want to develop it yourself, you could just loop through a range of ips and ping them, then retrieve the MAC address from your arp cache if you are on the same subnet. – Gregg Leventhal – 2013-09-30T15:48:20.523
And if I am not on the same subnet? – Lee – 2013-09-30T15:56:23.600
You cannot get MAC information from machines on a different subnet without querying a device which is on the same subnet as those machines. MAC is a layer 2 address which does not get routed across different network segments. – Gregg Leventhal – 2013-09-30T15:58:14.067
let us continue this discussion in chat
– Lee – 2013-09-30T16:00:55.187