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Old 27th May 2008, 22:18
toodles toodles is offline
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Originally Posted by cgick View Post
hi folks,

we are located in rz 6 which still allows some subnets to be used by two machines on virtual interfaces. our latest subnet which we registered though doesn't route to both machines any more.

did you get any feedback from hetzner? the support simply told me via e-mail that ha-solutions aren't supported any more and theres no alternative.

i read that virtual mac-addresses could do the job? maybe we could even fake the mac by the active machine to bypass that check. did anyone of you guys get information obout alternatives?

best regards,
Hi chris,

No feedback yet. Virtual mac-addresses can be made work (ask Hetzner to give you one), although it's not terribly nice. From what I understood, it works something like this.

server1 - macAddress1 - ipAddress1
server2 - macAddress2 - ipAddress2

virtualMacAddress3 - ipAddress3

You can now give either server1 or server2 the virtualMacAddress3 along with ipAddress3, but while it has this mac and ip address, it cannot have the original mac and therefor the original ip address. This means that your server will not ever have an ip address under which it is always available. You'll always have to try between ipAddress1 and ipAddress3 for server1 and for the second server it will always be either ipAddress2 or ipAddress3. It will make everything a lot more complicated.

Don't try and add "fake" mac addresses on your own. The switches remember your mac address and will not give out any IP address to a different mac address. This will mean that once the mac address is changed, you will no longer be able to connect to their network until your original mac address is restored. Your nic will "remember" the mac address, so even a reboot won't restore it, and because your machine will be disconnected from the network, an automated remote reboot will not work either. They will have to switch off your server for 10 minutes or change the mac address back manually.

Don't take my word for the above, this is only to the best of my knowledge. I wish I had better news.

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