#Show mac address cisco switch mac#
For each VLAN, get the MAC address table (using community string indexing ) dot1dTpFdbAddress (.1.3.6.1.2.1.17.4.3.1.1).
#Show mac address cisco switch how to#
It will show multiple MAC addresses on the uplink port that connects to other switches. The document is actually describing how to use SNMP to find out the port that a MAC address was learned on, but its a good starting point. That's why I showed it two different ways. Some switches/ios versions have a slight variation of the command. (ETA: What if you can't get to the Console port? How do you get the IP address of the switch in order to SSH or (if you must) Telnet in?)Ĭouldn't you just use CDP? #show cdp nei detail will show you the ip of the connected devices. Show mac-address table or show mac-address-table will give you the interface (the given name, not the name you assign it) and MAC Addresses. The amazing thing to me is, this far into the 21st Century, this is still the only way I could find to get this information - i.e. Also, 'sh ip arp | i 0/24' will show just the MAC address(es) on that port.) If you're all Cisco, 'show cdp neighbor' (or 'sh cdp nei') will get you to the next switch. Yes, each switchport has it's own MAC address, I think this is how the switch itself (ASICS) makes forwarding decisions. Normally, the vlan1 interface has this same MAC address. This is the mac address that is used in i.e STP.
(Small tip: When you see a large number of MAC addresses showing up on a single port, there's a switch on that port into which those MAC addresses are connected. When using the show version command, you will see 'Base ethernet MAC address: 0007.ECE1.5D18' in the output.
It helps to Ping the subnet's broadcast address (e.g. :^D After beating Google to death over it, hoping for some useful tool, I ended up using exactly the same process (plus the online MAC address lookup to ID the device manufacturer), so I can affirm this works perfectly, if you work it.Īs you can see, the 'sh arp' or 'sh ip arp' commands also give you the MAC addresses, so essentially the 'sh mac add' is only to get the port in which the device is connected. Each host connected to the network should maintain its own ARP table. If no ARP entry exists, an ARP broadcast is sent out, and the table is updated with the response. Thanks for posting this *after* I finished a "What's Connected Where" jihad on our network. Your switch should have a MAC/CAM Table as a layer of two devices, whereas The ARP address table is used to map MAC Addresses to IP addresses. When the switch receives a frame, it associates the MAC address of the transmitting interface with the recipient VLAN and port.