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Urfan Khaliq
Beginner

Switch MAC Address

Hi, Can anyone please help...I am trying to find out the MAC address that a 3560G would use for DHCP requests as it turns out it is not the base mac address you get from a show ver....

Is there a command to see the mac address(es) associated with a 3560G?

Much apprecieated

Urfan

29 REPLIES 29

Hi,

according to the page all interfaces can use the same mac address but I do not think that this is the case as you can see from the attached file...vlan1 and vlan2 (which i created as a test) both have different mac addresses....

Urfan

Urfan,

It depends on the platform, please see the table(Catalyst L2 and L3 Fixed Configuration Switches):

http://www.cisco.com/en/US/products/hw/switches/ps700/products_tech_note09186a00801c9b4e.shtml#fixed

bye

FCS

Please rate me if I helped.

So as im using the 3560 which has unique mac addresses per vlan and interface etc then is there a command for me to see the list of mac addresses that belong to the switch? (Which is my original question)

Urfan

Hi Urfan

Try this

switch# sh int | include line protocol | Hardware

Jon

Hi Jon,

Thanks for that but its not quite what I was looking for...I am after a complete list of all MAC addresses for the switch...(and not connected devices)...I attach the output I recieve from sh interfaces | include line | EtherSVI

Many Thanks

Hi Urfan

Apologies if i am still not understanding but the following command "sh int | include line protocol | Hardware" (note NOT "sh int | include line | EtherSVI) gives the following

SW1#sh int | include line protocol | Hardware

Vlan1 is up, line protocol is up

Hardware is EtherSVI, address is 0019.060d.1c40 (bia 0019.060d.1c40)

FastEthernet0/1 is up, line protocol is up (connected)

Hardware is Fast Ethernet, address is 0019.060d.1c03 (bia 0019.060d.1c03)

FastEthernet0/2 is up, line protocol is up (connected)

Hardware is Fast Ethernet, address is 0019.060d.1c04 (bia 0019.060d.1c04)

FastEthernet0/3 is up, line protocol is up (connected)

Hardware is Fast Ethernet, address is 0019.060d.1c05 (bia 0019.060d.1c05)

FastEthernet0/4 is down, line protocol is down (notconnect)

Hardware is Fast Ethernet, address is 0019.060d.1c06 (bia 0019.060d.1c06)

FastEthernet0/5 is down, line protocol is down (notconnect)

Hardware is Fast Ethernet, address is 0019.060d.1c07 (bia 0019.060d.1c07)

FastEthernet0/6 is down, line protocol is down (notconnect)

Hardware is Fast Ethernet, address is 0019.060d.1c08 (bia 0019.060d.1c08)

FastEthernet0/7 is down, line protocol is down (notconnect)

Hardware is Fast Ethernet, address is 0019.060d.1c09 (bia 0019.060d.1c09)

FastEthernet0/8 is down, line protocol is down (notconnect)

Hardware is Fast Ethernet, address is 0019.060d.1c0a (bia 0019.060d.1c0a)

FastEthernet0/9 is down, line protocol is down (notconnect)

Hardware is Fast Ethernet, address is 0019.060d.1c0b (bia 0019.060d.1c0b)

FastEthernet0/10 is up, line protocol is up (connected)

Hardware is Fast Ethernet, address is 0019.060d.1c0c (bia 0019.060d.1c0c)

FastEthernet0/11 is up, line protocol is up (connected)

Hardware is Fast Ethernet, address is 0019.060d.1c0d (bia 0019.060d.1c0d)

FastEthernet0/12 is down, line protocol is down (notconnect)

Hardware is Fast Ethernet, address is 0019.060d.1c0e (bia 0019.060d.1c0e)

FastEthernet0/13 is down, line protocol is down (notconnect)

Hardware is Fast Ethernet, address is 0019.060d.1c0f (bia 0019.060d.1c0f)

FastEthernet0/14 is down, line protocol is down (notconnect)

Hardware is Fast Ethernet, address is 0019.060d.1c10 (bia 0019.060d.1c10)

FastEthernet0/15 is up, line protocol is up (connected)

Hardware is Fast Ethernet, address is 0019.060d.1c11 (bia 0019.060d.1c11)

FastEthernet0/16 is up, line protocol is up (connected)

Hardware is Fast Ethernet, address is 0019.060d.1c12 (bia 0019.060d.1c12)

FastEthernet0/17 is up, line protocol is up (connected)

Hardware is Fast Ethernet, address is 0019.060d.1c13 (bia 0019.060d.1c13)

FastEthernet0/18 is up, line protocol is up (connected)

Hardware is Fast Ethernet, address is 0019.060d.1c14 (bia 0019.060d.1c14)

FastEthernet0/19 is up, line protocol is up (connected)

Hardware is Fast Ethernet, address is 0019.060d.1c15 (bia 0019.060d.1c15)

FastEthernet0/20 is down, line protocol is down (notconnect)

Hardware is Fast Ethernet, address is 0019.060d.1c16 (bia 0019.060d.1c16)

FastEthernet0/21 is up, line protocol is up (connected)

Hardware is Fast Ethernet, address is 0019.060d.1c17 (bia 0019.060d.1c17)

FastEthernet0/22 is administratively down, line protocol is down (disabled)

Hardware is Fast Ethernet, address is 0019.060d.1c18 (bia 0019.060d.1c18)

FastEthernet0/23 is administratively down, line protocol is down (disabled)

Hardware is Fast Ethernet, address is 0019.060d.1c19 (bia 0019.060d.1c19)

FastEthernet0/24 is administratively down, line protocol is down (disabled)

Hardware is Fast Ethernet, address is 0019.060d.1c1a (bia 0019.060d.1c1a)

GigabitEthernet0/1 is down, line protocol is down (notconnect)

Hardware is Gigabit Ethernet, address is 0019.060d.1c01 (bia 0019.060d.1c01)

GigabitEthernet0/2 is down, line protocol is down (notconnect)

Hardware is Gigabit Ethernet, address is 0019.060d.1c02 (bia 0019.060d.1c02)

Jon

View solution in original post

Thanks very much!

:-)

Not a nice solution, but works :)

sh interfaces | include line | EtherSVI

if your vlan number is 1 and the Base MAC address is 00:12:00:90:8B:00, then the VLAN1 MAC address is 00:12:00:90:8B:01, VLAN2 00:12:00:90:8B:02

bye

FCS

Please rate me if I helped.

Again I think you are mistaken as you can see from the output...my base mac address is 00:1E:49:A3:1D:00 and my vlan 1 is 001e.49a3.1d40 which is clearly not just one up from the base...

(see show ver and show int vlan 1 attached..) :-)

Many thanks

Urfan

Again I think you are mistaken as you can see from the output...my base mac address is 00:1E:49:A3:1D:00 and my vlan 1 is 001e.49a3.1d40 which is clearly not just one up from the base...

(see show ver and show int vlan 1 attached..) :-)

Many thanks

Urfan

Sir,

If you correctly checked the site, what I sent http://www.cisco.com/en/US/products/hw/switches/ps700/products_tech_note09186a00801c9b4e.shtml#fixed

you saw that there is a show command which shows all interfaces' MAC. I thought you need only the SVI's MAC.

2950#show interfaces | include line | address

Output is similar than

2950#show interfaces | include line | Hardware

bye

FCS

Again I think you are mistaken as you can see from the output...my base mac address is 00:1E:49:A3:1D:00 and my vlan 1 is 001e.49a3.1d40 which is clearly not just one up from the base...

(see show ver and show int vlan 1 attached..) :-)

Many thanks

Urfan

Urfan,

You are right with the base mac and vlan mac relation issue (I've just made a quick check on one of my device).

But the command what is on the sent link works.

bye

FCS

Please rate me if I helped.

Oliver Gorwits
Beginner

Hi Urfan,

I had the same question as you. Here is what I found out, for reference:

The CPU on a 3560 or 3750 has a stash of 64 MAC addresses allocated when the device is built, for SVI (vlan interfaces). It also has another 64 addresses for the physical ports.

You can get the "base" MAC address by doing a show version. The first 64 addresses from that address are used for physical ports. The next 64 from that address are used for SVI (vlan) interfaces.

The CPU allocates MAC addresses to vlan interfaces in the order which the interfaces are created, so they can change after a reboot of the switch. If you use more than 64 vlan interfaces, the rest all get the same MAC address as the 64th interface.

For example:

base address: xx:xx:xx:xx:3e:00

first vlan address: xx:xx:xx:xx:3e:40 (this is base + 64)

last vlan address: xx:xx:xx:xx:3e:7f (this is base + 127)

So in answer to your question, the MAC address used for DHCP will depend on the interface used, but is probably no more than 127 higher than the base address. Also, the commands posted in this thread to show the MAC addresses only show those currently in use, and not those available in the future. I don't know whether there are even more MAC addresses allocated to the switch for other purposes, sorry.

You might also find the following page interesting:

http://www.cisco.com/en/US/products/hw/switches/ps700/products_tech_note09186a00801c9b4e.shtml

[Supported Platforms for Unique MAC Address Configuration on VLAN or L3 Interfaces for Catalyst Switches]

I hope all this helps, and helps other people!

regards,

oliver.