Changing MAC address

[Arunvijai_4]

Hi All,

I need to change a Ethernet card's MAC address to 00:00:00:00 and test few things. What is the best way to do? I will have to revert it back after testing.

[Pete Randall]

The -A option of the lanadmin command will change MAC address on a temporary basis. Permanent changes would have to be made to the appropriate /etc/rc.config.d/hp*conf file, but it sounds like you just need temporary.


Pete

[Arunvijai_4]

Thanks Pete. Can you please tell the exact syntax? This is my output of lanscan,

# lanscan
Hardware Station Crd Hdw Net-Interface NM MAC HP-DLPI DLPI
Path Address In# State NamePPA ID Type Support Mjr#
0/0/0/0 0x001083F515F1 0 UP lan0 snap0 1 ETHER Yes 119
0/5/0/0 0x001083F6CD7E 1 UP lan1 snap1 2 ETHER Yes 119
0/12/0/0 0x00306E0672D1 2 UP lan2 snap2 3 ETHER Yes 119


I want to change for lan1 or lan2. How do i do that?

[Jestin John Chacko]

Dear

I think we can change the station address using sam.

[Hakki Aydin Ucar]

you can change the MAC address in SAM by selecting Networking and Communications, then selecting the interface, then Action, Modify, Advanced Options. HP-UX refers to the MAC address as the "station address".

[Pete Randall · Accepted solution]

For lan1:

lanadmin -A 0x00000000 1

where "1" is the PPA number from lanscan. Also, note this warning from the man page:

"Set the new station address of the interface corresponding to PPA. The station_addr must be entered in hex format with a '0x' prefix. You must have superuser privileges. When station_addr is DEFAULT, the factory default physical address will be restored. WARNING: To ensure the interface and the system work correctly, the interface MUST be brought down before setting the new station address. After the new station address is set, the interface should be brought up in order to be functional. See ifconfig(1M) for bringing down and bringing up the interface."


Pete

[Arunvijai_4]

Excellent! Thanks folks.

[santosh_12_1]

HI Arun,
We both are trying to zero-in on the same issue.
You may find assitional info here:

http://forums11.itrc.hp.com/service/forums/questionanswer.do?threadId=1364524&admit=109447626+1250620267464+28353475

[rick jones]

OK, I'll ask the elephant in the middle of the room question - why do you want to set an HP-UX's NIC's MAC address to all zeros?

[Arunvijai_4]

I brought down the interface and tried to change MAC address using SAM, but getting this error

â ERROR: lan1 interface | PPA 1 : error: expected primitive 0x06, got â â dâ
â â â â DL_ERROR_ACK â â â â
â â â dl_error_primitive = 0x33 â â â
â â â dl_errno = 0x04 â â â
â â â â dl_unix_errno = 22 â â â
â â â â change_phys_addr: unable to change physical address â â â
â â â â Old Station Address = 0x001083f6cd7e

[Arunvijai_4]

Tried with lanadmin, didn't succeed though

# lanadmin -A 0x000000000000 1
Old Station Address = 0x001083f6cd7e
error: expected primitive 0x06, got DL_ERROR_ACK
dl_error_primitive = 0x33
dl_errno = 0x04
dl_unix_errno = 22
change_phys_addr: unable to change physical address

[Arunvijai_4]

I am trying to simulate and test a customer issue.

[Roland Piette]

Hi Arunvijai,

Before using lanadmin -A command you need to bring down your interface with ifconfig command. After setting the new address the interface will be bring up.

To get back the factory address you can use -A DEFAULT keywords in lanadmin command.

Regards

[rick jones]

I suspect this bringing down the interface would include an "unplumb" ifconfig command.

The only place I would initially see a MAC address of all zeros would be a broken NIC, which would seem to be a HW replacement issue?

[Arunvijai_4]

Yes, I brought down and unplumb the interface and tried changing using lanadmin -A; still the same error persists.

[rick jones]

It is quite possible that the code in the kernel is making some sanity checks of the MAC address and deciding it does not like the MAC address at all (not surprising since all zeros used to be - long long long ago - a broadcast address). You might try changing just a single bit or two from the existing MAC address and try setting the card to that - I would change a couple bits in the middle somewhere.