One IP for several Interfaces

[Simon Hobson]

Daniel Thielking <Daniel.Thielking at ias.rwth-aachen.de> wrote:

> host laptop-2-lan {
>   hardware ethernet 18:03:73:7a:61:dd;
>   fixed-address laptop-2.my.domain;
> }
> 
> host laptop-2-wireless {
>   hardware ethernet 38:59:F9:0F:1D:ED;
>   fixed-address laptop-2.my.domain;
> }
> 
> behind the laptop-2.my.domain DNS-Name ist one ip(192.168.1.32) configured in bind.
> 
> Now to the problem:
> 
> If I use laptop-2 in wireless mode everything works fine. If I want to use a cable both Interfaces are getting the same address. It manifests itself in a ip address conflict. How can I configure DHCPd to avoid this? But I do not want to use more than one address. 

OK, firstly it's not really "a DHCP problem".
The only way to completely fix it is to ensure that only one interface is active at any time - that's easier said than done. However, I've (in the past) done exactly the same thing and it's worked just fine - client is Apple laptop running OS X. AFAICT OS X doesn't complain if you configure the same IP on two interfaces - it just uses the one that's configured to be higher up the list.

What is the client in your case ?