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I need a list of all devices that are directly connected to the cisco device I'm connected to through serial. I tried the arp table, but it contains more entries than I want since it spans multiple switches. I have no idea how to know which one is an end user device and which one is another network device.

I'm basically crawling a network and I need to know where to go next.

EDIT: This is a general cisco-device question. I want to do this from routers, switches and other.

I'm running the commands on a cisco device, looking for any device (not necessarily a cisco device) that is directly connected. And I would also like to know which ones of those devices are other network devices (regardless of brand) and which ones are end users.

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    More information would be required to give this a proper answer. To start with, is the Cisco device you are connected to a switch, a router, or some other device?
    – YLearn
    Commented Jul 29, 2014 at 17:02
  • Did any answer help you? if so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you could provide and accept your own answer.
    – Ron Maupin ♦
    Commented Aug 10, 2017 at 4:58

3 Answers 3

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You can get some intel on it with the command show mac-address-table vlan <number>. It shows all the dynamically learned MACs and the ports they were learned on. You could then decide, based on your network, if said ports are connected to a switch or end device.

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  • what's the difference between the info shown in show mac-address-table compared to show ip arp?
    – Drathier
    Commented Jul 29, 2014 at 18:36
  • @FilipHaglund The MAC address table contains layer two information needed for switching: which MAC addresses live on which ports. The ARP table contains a mapping of IP addresses to MAC addresses, needed to send out IP packets in ethernet frames.
    – Gerben
    Commented Jul 29, 2014 at 18:43
  • yeah sure, but show ip arp lists the interfaces as well?
    – Drathier
    Commented Jul 29, 2014 at 19:08
  • No. ARP table shows only which MAC maps to which IP address.
    – Pedro Brito
    Commented Jul 29, 2014 at 19:57
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    BLA#show arp vlan 2 | i a4ba.db03.d2c8 Internet XX.XX.128.100 0 a4ba.db03.d2c8 ARPA Vlan2 Refers to logical interface BLA#show mac-address-table vlan 2 | i a4ba.db03.d2c8 * 2 a4ba.db03.d2c8 dynamic Yes 0 Gi4/48 Refers to physical port
    – Pedro Brito
    Commented Jul 29, 2014 at 20:43
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Using show CDP neighbors detail you will get this info:

Device ID:
Entry address(es): 
IP address:
Platform:
Capabilities: 
Interface:
Port ID (outgoing port):
Holdtime :
Version :
advertisement version: 
Protocol Hello:
VTP Management Domain:
Duplex:
Management address(es):

BUT IP is not a good identifier because it could be modified manually, I would prefer to use show version or show inventory to get the serial number of the device.

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If you are on a cisco device use show cdp neighbors

That will show all Cisco devices that are directly connected. Helpful for spotting Network devices. You will not get workstation info, but other cisco switches, routers, etc...

You may also get some IP phones on that list.

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