CDP neighbors

[vishalpatil86]

hi,

i have edge switch to which all my users are connected.

Is there any command to get user's IP like we do in show cdp neighbors r is there any way to do it

pleasw help on this!!!!!!!!!!!

[milan.kulik]

Hi,

if it's an L2-only switch, the only way is:

sh ARP

on the default-gateway router.

And correlate with user MAC addresses shown by

sh mac-address-table

on the edge switch.

HTH,

Milan

[nkarpysh]

Hello Vishal,

No specific tool for that. Though you can do following. Take particular VLAN - you will need to have SVI for that VLAN configured. Ping broadcast address for that subnet (e.g. if subnet is 10.1.1.0 /24 - then broadcast for it is 10.1.1.255). All the hosts withing this subnet will eb ARPed first and then reply to ping.

Then check show ip arp on your switch for this subnet - you will see all the hosts replied and their mac addresses.

Do show mac address-table address MAC_ADDR from above and you will see to whcih port that is connected. You will have to do it one by one or write some script.

Hope this helps,

Nik

[fb_webuser]

As I know you can only see the mac-address table on switch. Switch is not interested in end node IPs

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Posted by WebUser Aleksandr Yanovskiy

[fb_webuser]

Nik, have you ever tried to ping broadcast address in LAN? Most modern OS doesn't reply for broadcast ping

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Posted by WebUser Aleksandr Yanovskiy

[John Blakley]

Vishal,

Download nmap and run that. It'll show you all addresses in use and responding.

nmap -sP 192.168.0.0/24