How to set/display the MAC of a virtual IP

[Alan Edwards]

How do you set or display the MAC address of a virtual IP? This is in a Cluster.

Alan

[Patrick Wallek]

The virtual IP will use whatever the MAC address is of the interface it is configured on. If your virtual interface is lan1:1, then the MAC address used will be the one for lan1.

I don't think there is a way to change that. I don't think you would want to change that anyway.

[Rick Garland]

You can see the MAC addresses with the 'lanscan' command

[Alan Edwards]

Yes, and I am familiar with lanscan. It is just that our NetOps dept is saying that they are seeing all zero's for the MAC associated with the virtual IP at times.

The only command that seems to show the MAC is arp, and you have to know which IP is the virtual one. Other OS's show the MAC with all IP's with the ifconfig command.

Alan

[Steven E. Protter]

Shalom Alan,

Yes it is possible to set the MAC address of the virtual IP.

Is there a reason why you wish to do that?

The MAC address is supposed to be unique to each Network Card. Modern wireless routers let you clone MAC addresses to make access easier, but I've found a hands off policy with MAC addresses avoids issues, like to MAC addresses the same on the same LAN.

ServiceGuard manuals tell you to check linkloop which uses the MAC address. I sense the possibility of making a mistake that harms cluster reliability.

SEP

[Alan Edwards]

Shalom Steve.

It is more a matter of needing to see the MAC, the Cluster software will assign it based on which physical interface is used.

I guess what I am saying is that is there an improved ifconfig for HP-UX ?

Alan

[Ralph Grothe]

I think you relate to e.g. the Linux incantation of ifconfig which indeed along with the MAC address shows a whole host of other useful information.
On HP-UX, apart from using the lanscan command, you could as well use lanadmin to either display or even change a NIC's MAC (which I wouldn't recommend).

e.g.

your interface being lan2:1

$ /usr/sbin/lanadmin -a 2

whereas something like this should change the MAC (replace char set with actual address)

# /usr/sbin/lanadmin -A 0x[0-9a-f]{12} 2

[Jim Keeble]

I wonder how the netops people are finding this all 0's mac address? Is it after a failover to a standby card or an adoptive node?

If the virtual IP always works, it's probably more of a reporting problem than the IP really trying to use an all 0's mac. Maybe the HP isn't updating a MIB that they are retrieving their data from via snmp?