connectivity issues after changing the mac address on SVI interface

Unanswered Question
Sep 11th, 2010


after changing the mac address of an SVI on a 2950 switch  the interface became unpingable.

The following note can be found here

Note: In Cisco IOS Software Release 12.1(13)EA1 and earlier, the switch allows configuration of the mac-address command in the interface. But this command causes connectivity issues. This command-line interface (CLI) configuration issue has been fixed in Cisco IOS Software Release 12.1(14)EA and later.

But the switch is running the latest IOS to date:  12.1(22)EA13.

the following is the configuration of the SVI

interface Vlan1

ip address

mac-address aaaa.bbbb.cccc

any help ?

I have this problem too.
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Nagaraja Thanthry Sat, 09/11/2010 - 11:39


After changing the MAC address on the interface, have you cleared the ARP

cache on the PC/Switch? Can you check the PC's ARP cache to make sure that

you have the correct MAC entry for the switch IP?



hanicisco Sun, 09/12/2010 - 00:34


Yes I have cleared the ARP cash. The PC is getting the new MAC address in response to the ARP request, but the ping fails.



Nagaraja Thanthry Sun, 09/12/2010 - 07:15

Hello HH,

It seems like the image 12.2(22)EA13 does have the issue with MAC address

change. The switch exhibited the same behavior in one of my lab setup.

Unfortunately, even it if it is a bug, there is not much anybody could do

about it as 2950 is end-of-life product and there are no new software

development/patches for that hardware.



hanicisco Mon, 09/13/2010 - 01:37

Hello NT

thank you for your cooperation.

unfortunately you have confirmed my doubts.

this is most inconvenient because I have 2 switches on my LAN with the SAME BIA (000d.286e.0b40)

and if i cannot change the mac addresse of one of them, i'm not gonna be able to manage them remotely.

any idea for a workaround for this issue ????



Nagaraja Thanthry Sat, 09/11/2010 - 11:45


Please remove the following line from the configuration:

nat (inside) 1

Also, what is the IP of the DNS server you are using? Could you use

as your DNS server and see if that helps?



Reza Sharifi Sat, 09/11/2010 - 11:48


The note you provided from this document is for 3500 series switches.  You are using 2900 series and under the same section it says:

The Catalyst 2900XL/3500XL switches recognize the mac-addresscommand but do not accept or support the command. This output is from a Catalyst 3500XL with Cisco IOS Software Release 12.0(5)WC3b:



hanicisco Sun, 09/12/2010 - 00:57

Hi Reza,

the note you gave concerns the 2900XL/3500XL.

I am using a  C2950G-24-EI , which is concerned

according to the document, the note i gave "pertains to the Catalyst L2 fixed configuration switches 2940, 2950/2955 and 2970 (VLAN interface) as well as the Catalyst L3 fixed configuration switches 3550, 3560 and 3750 (VLAN and L3 interface)"




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