John Hascall john at
Mon May 1 18:46:42 UTC 2006

> Mike Diggins wrote:
> >I am considering enabling the 'one-lease-per-client' option in DHCPD for
> >my student network.

> What should be more of a concern would be devices (such as laptops) 
> that have more than one interface - in which case, it could get an 
> address on the wired network, sign in on the wireless, and the server 
> will silently cancel the lease on the wired network. In this case, 
> the client can continue using an address that the server now thinks 
> is free - and if it tried to lease it to another client, it will get 
> a reply to a ping and mark the address as abandoned.

   I've never seen this and we've run with 'one-lease-per-client'
   for as long as I can remember.  Also it seems to me that this
   would only be possible if both the wired and wireless interfaces
   sent the same 'client-id' which I would think would be rare.

   We have the opposite problem.  Our users *really* want to have
   the same domain-name whether they are on wired or wireless and
   if they accidentally have both interfaces on it is (to them)
   random and indeterminate which IP address gets associated with
   the domain name.  So, I'd love to be able to say:

     one-lease-per-client on;
     host foo {
          hardware ethernet 00:11:22:11:11:11;
          hardware ethernet 00:11:22:22:22:22;
          ddns-hostname "whatever";
          ddns-domainname "";
          option domain-name "";

   and have a lease on one interface cancel any lease on the other.

PS, I know, a pipe dream...

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