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Preventing bvi from getting a random mac address

It's not a big problem I have, because the connection is basically working, but I don't seem to be able to get rid of messages in the log of my 870w router like:

Note: A random mac address of 0000.0cb7.25cc

has been chosen for BVI in bridge group 1 since there is no mac address

associated with the selected interface.

I have other 2 bvis, and for bvi 3 I get the error

Note: A random mac address of 0000.0cb7.261c

has been chosen for BVI in bridge group 3 since the selected mac address

is already being used by Bridge Group 2.

And then again for bvi 1:

Note: A random Spanning Tree Bridge Identifier address of 0000.0c21.2698

has been chosen for Bridge Group 1 since there is no mac address

associated with the selected interface.

For the record: I use rfc 1483 bridged adsl, and bvi 1 is the bridge to the provider, getting the ip address from the provider via dhcp.

So far I have been trying only to remove the messages for bvi 1, because it's the most important interface. I used to give bvi 1 an address with the line

ip address dhcp client-id vlan 1

but I can't give vlan 1 a fixed mac address. So I tried to give bvi 1 a fixed mac address, and I tried to use fastethernet 0 instead of vlan 1 to give bvi 1 a client-id (fastethernet can have a fixed mac), but that doesn't seem to work.

As I said, connection is basically working, because my provider doesn't look at the mac address. However, the fact that I can't have a fixed mac, especially on bridge group 1, can be a problem in case I need to talk to my provider: I don't have a fixed mac address to give that they can look up in the log.

Any suggestion welcome. Thanks

2 REPLIES
Silver

Re: Preventing bvi from getting a random mac address

The bridge identifier on a router is chosen by several facts. The mac address of a bridge group may come from one of the ethernet interfaces or generated randomly by a router. When you configure bridge on a non-ethernet interface, bridge identifier will be randomly generated by the router's software and it will probably display a warning message something like this:

"A random Spanning Tree Bridge Identifier address of 0000.0c21.2698 has been chosen for Bridge Group 1 since there is no mac address associated with the selected interface." So ensure that this address is unique.

New Member

Re: Preventing bvi from getting a random mac address

I looked at it again and I saw that if I assign a mac address to bvi 1 that address is actually the one given to the provider, as shown by the 'show arp' command. I don't know how I missed that. Therefore my problem seems now to be not so important. The only weird thing is that the messages in the log stay, and I can't find the addresses mentioned in the log anywhere.

I have to say that I'm still curious. I have defined fastEthernet 0 as follows:

interface FastEthernet0

mac-address 0000.0c5b.25c4

no ip address

no cdp enable

and bvi 1 as follows:

interface BVI1

description $FW_OUTSIDE$

mac-address 0000.0c58.25cc

ip address dhcp client-id FastEthernet0

ip access-group globalInbound in

ip access-group globalOutbound out

no ip redirects

no ip unreachables

no ip proxy-arp

ip inspect ftpInspect out

ip nat outside

ip virtual-reassembly

ip route-cache flow

but I still get those two messages.

Strange enough, setting the mac address for bvi 2 and 3 was enough to get rid of a similar message for bvi 3.

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