best practice for moving subnets?

[Tom Schmitt]

> Datum: Wed, 17 Nov 2010 07:42:40 +0100
> Von: Bjarne Blichfeldt <bjb at jndata.dk>
> Betreff: RE: best practice for moving subnets?

> > I want to move a few subnets from one dhcpd failoverpair to another
> > dhcpd failoverpair and was asked if I could do that without causing the
> > dynamic clients to loose their connection to the network (or their ip 
> > address).
> > 
> 
> I think I would :
> 
> add the subnets to the new failoverpair
> change helper addresses
> change the config for the relevant subnets on the old pair to include :
> 	# 1 = DHCPDISCOVER
>              if option dhcp-message-type = 1 {
>                         deny booting;
>               }
>             deny after 4 2010/12/28 16:00:00;
> or something suitable.
> 
> The thing is, even if you change helper address, the clients will continue
> to use the old dhcp serves if there are
> network connectivity.
> Only discoveries are sent as broadcast make use of the helper address.
> DHCPINFORM, DHCPREQUEST will be sent directly to the previous
> used dhcp sever.
> 

Yes, I thought about this problem. Could that problem be avoided if I add something like this to the config of the old server pair?

         next server = address_of_new_server;



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