mac address change on an eth alias

root@k:~# ifconfig eth0:1 123.123.123.123 netmask 255.255.255.0 hw ether
00:E0:7D:02:C6:0C
SIOCSIFHWADDR: Device or resource busy
root@k:~#

am I trying to do something impossible or is it only my NIC (Realtek 8139) that can't do it ?

I want to have 2 ip's on the same interface - but with 2 different macs ... why? because this is my testing server and, among others (dhcp, bind, sendmail/postfix, asterisk, etc) I want to actually see how a mac address can be changed ... if it's possible

thank you for you patience,

petre

Quoted 7 lines

root@k:~# ifconfig eth0:1 123.123.123.123 netmask 255.255.255.0 hw ether
00:E0:7D:02:C6:0C
SIOCSIFHWADDR: Device or resource busy
root@k:~#

am I trying to do something impossible or is it only my NIC (Realtek 8139) that can't do it ?

AFAIK yes, at least the way you are doing it, you can however change a MAC adress before configuring the card.

ifconfig eth0 00:E0:7D:02:C6:0C
ifconfig eth0 123.123.123 netmask 255.255.255.0

So what i am saying is, you cant change the MAC address when a IP# is assigned.

I tested it on my eth0 interface but without aliasing, but i doubt if that is an issue here.

Quoted 4 lines

I want to have 2 ip's on the same interface - but with 2 different macs ... why? because this is my testing server and, among others (dhcp, bind, sendmail/postfix, asterisk, etc) I want to actually see how a mac address can be changed ... if it's possible

Down the IFC's, change the MAC(s), then configure the card and its aliases.

Quoted 3 lines

thank you for you patience,

petre

richard,

thanks for the answer; it is as you said, except I didn't manage to put 2 different macs

ifconfig eth0 hw ether 00:02:44:11:AA:AA ifconfig eth0:1 hw ether 00:02:44:11:AA:AB ifconfig eth0 some_IP netmask 255.255.255.0 ifconfig eth0:1 123.123.123.123 netmask 255.255.255.0

and the result is both have the same mac (the last one issued with ifconfig)

so I didn't get what I wanted - the mac of the alias being different than the interface's; should I presume "no can do" ?

thanks,

petre

On Tuesday 17 December 2002 21:55, Petre Bandac wrote:
[...]

Quoted 2 lines

so I didn't get what I wanted - the mac of the alias being different than the interface's; should I presume "no can do" ?

I myself have never used aliasing, i do however need to spoof my MAC sometimes on my laptop to be able to use it on other locations for my work. However thats beside the point, as far as i can see if you set a different IP# then the need for another MAC is (AFAIK) not nessasary.
If ARP's are a problem then setting static arps may be an answer, once more i have no experiance with alising, possably Ray may have some advise for you.

Quoted 6 lines · At 10:06 PM 12/17/02 +0000, pa3gcu wrote:

On Tuesday 17 December 2002 21:55, Petre Bandac wrote:
[...]

Quoted 2 lines

so I didn't get what I wanted - the mac of the alias being different than the interface's; should I presume "no can do" ?

Quoted 7 lines

I myself have never used aliasing, i do however need to spoof my MAC sometimes on my laptop to be able to use it on other locations for my work. However thats beside the point, as far as i can see if you set a different IP# then the need for another MAC is (AFAIK) not nessasary. If ARP's are a problem then setting static arps may be an answer, once more i have no experiance with alising, possably Ray may have some advise for you.

Afraid not; I've never actually used aliasing (except in trivial test setups).

Perhaps the best next step would be for you to explain why you need the interfaces to respond as though they were on different physical devices (that is, NICs with distinct MAC addresses). With that information, then maybe someone here could suggest a workaround. But as far as I know, NICs only support a single MAC address at any moment, not multiple ones.

just testing for my general knowledge

I heard that I can change the mac, I did as richard said and it went ok, and furthermore I wanted to change the mac of the alias, which I didn't succeed (richard's receipt gave the same mac - the mac I specifically assigned to the alias - to both IFC and it's alias)

so, I should take the final answer as no ?

thanks,

petre