DDNS update for hosts with fixed address

[Simon Hobson]

Marc Muehlfeld wrote:

>My DDNS update is working fine for all hosts getting the address out 
>of the pool. For the ones with fixed addresses entries are not 
>created in Bind. Is this a normal behavior or a missconfiguration?

It's normal behaviour. Static assignments don't go through the lease 
lifecycle and so there are no triggers to manage DDNS.

However, there is an option (IIRC it's something like 
update-static-leases) that will make the server do a DDNS update 
whenever it issues a 'static lease'. It's not generally advised to 
leave this on for two reasons :
1) it never does DDNS deletes - because there is no lease to expire, 
DNS entries are never removed.
2) It does a DNS update EVERY time a static lease is issued which may 
be a significant load on the DHCP and DNS services.

I believe the latest version of the server supports the concept of a 
"reserved lease" - you can flag a lease (by editing the lease file) 
as reserved and it won't ever be allocated to another client. But it 
still goes through the lease lifecycle management, so DDNS works 
correctly with the right updates and deletes.