Private MAC Address range

[ifabrizio]

Dear all,

I want to configure a MAC address on my asa 5520 interface.I ask you if exist a private MAC adrress range?

Thanks & Regards,

Igor.

[Richard Burts]

Igor

In Ethernet MAC addresses the low order bit of the first byte indicates locally administered addressing (it is sometimes referred to as the LAA bit). If it is set to 1 it indicates that this is not the burned in MAC but is an assigned MAC. So any Ethernet MAC that starts with 01 is effectively a private MAC.

HTH

Rick

[ifabrizio]

Dear Rick,

thanks for your fast response.

Ok, so I will do:

This is the burned in MAC :00-18-19-9e-79-cc

the First private assigned MAC is: 01-18-19-9e-79-cc ?

The second private assigned Mac is 03-18-19-9e-79-cc ?

I have a lot of subinterfaces.

Best regards,

Igor.

[Richard Burts · Accepted solution]

Igor

While your certainly can do:

01-18-19-9e-79-cc

03-18-19-9e-79-cc

05-18-19-9e-79-cc

...

there is really not need to keep the lower part of the address the same. So you could also do:

01-01-01-01-01-01

01-02-02-02-02-02

01-03-03-03-03-03

or any pattern that makes sense to you.

HTH

Rick

[Utair Corporation]

This is incorrect answers.

Least significant bit of the first octet identifies multicast address.

Second least significant bit identifies local/global assignment.

So correct MACs shold have 'xxxxxx10' bits set in first octet, like 02, 06, 0A and so on.

[Richard Burts]

You are correct about this (+5 for the correction) and my post was not correct about which bit to manipulate. Thank you for catching this and supplying the correct information.

HTH

Rick