#Show mac address cisco router how to#

If you absolutely have no idea which ones are which, you can try this:

If you have a more basic switch, then it could just be all fastethernet ports and you'll need to know which ones go between switches, but if you have gigabitethernet ports, then typically your interswitch links or trunks will go through those. The interconnecting ports, often linked via fiber these days, will typically be higher numbered ports. What you need to be aware of are what port numbers link switches together. This is normal, as other switches will learn and their CAM tables will add known MAC addresses as frames move through the network. Also, if you have a network larger than 200 nodes, this will definitely help if you have to do it the way I did, even if you do have physical access, because the legwork alone may take days. In doing so, knowing the location of system host names, I was able to more accurately map where each switchport went to without having to beg for authorization after hours to investigate this from each physical location. I used a combination of the command line (Windows 7) and telnet to access the main switches of our network to figure out what is on the end of each switchport. I was unable to perform this task with Spiceworks due to settings our manager imposed, so I had to find a workaround to get the job done.

I could, however access all the switches, but not our router, and routing is not enabled on our switches anyway, though they are layer 3 capable (pretty much a flat network).

#Show mac address cisco router how to#

How to Configure IPv6 Static and Default Routes.NOTE: This how-to is based on the premise that you have switches with ports that you don't know where they are going, no inter-vlan routing, and do not have access (due to permission restrictions) to some of Spiceworks application features.ДЄ while back I was trying to figure out how to map our network, switchports in particular, but could not gain access to the whole building to test from the wall jacks and/or nodes on our network. Using the show ipv6 interface fa0/1 command, the MAC address is displayed as part of the IPv6 address with the Hex characters FFFE (16 bits) added in the middle, which expands the 48-bit MAC address to create the IPv6 64-bit link-local address. The MAC address of the Ethernet Fa0/1 interface is 0260.3d47.1720. The EUI-64 option is used to create the 64-bit MAC address. R1(config)# ipv6 unicast-routing ( configure the router to activate IPv6 routing and configure the router fa0/1 interface). You must specify the entire 128-bit IPv6 address or specify to use the 64-bit prefix by using the eui -64 option.ДЇrom the above IPv6 address configuration example, router1 is shown connected to an IPv6 WAN to router2 with a subnet prefix address of 2001:db8:3c4d:2::/64. When a network router interface is configured with an ipv6 address, a link-local address willВ be configuredВ automatically for the interface. then you must configure each interface that requires IPv6.Д¬ommand syntax for enabling IPv6 on Cisco routers: First, you must activate IPv6 traffic-forwarding on the router, and There are two basic steps used to activate IPv6 on a Cisco router: The global configuration command must be used in both Stateful ( DHCPv6) and Stateless autoconfiguration. It must be activated between interfaces by using the global configuration command вЂ“ ipv6 unicast-routing. By default, IPv6 traffic-forwarding is disabled on a Cisco router.