Re: Duplicate MAC address

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Re: Duplicate MAC address

I’ll try to explain more detail

ISP registered my MAC address which is 1111.1111.1111

L2 Switchports has MAC 2222.2222.2222

BVI Interface has MAC 1111.1111.1111

interface FastEthernet0
interface Vlan1
no ip address
bridge-group 1
interface BVI1
mac-address 1111.1111.1111
ip address dhcp
no ip redirects
ip directed-broadcast
ip nat outside
ip virtual-reassembly
zone-member security OUTSIDE
crypto map rtp

In this case of configuration, everything works good, but sometimes ISP DHCP Server stops giving me an IP Address because it sees both 1111.1111.1111 and 2222.2222.2222 MAC addressess.

I can change MAC address of the switchport interface (which is 2222.2222.2222) to registered mac – 1111.1111.1111 and remove BVI interface in hope that VLAN interface will get IP address but it will not work because regardless of the switchport mac setting, it will always have its native mac.