Setting CNAMES via ddns from dhcp3

[Chris Searle <chris@chrissearle.org>]

Running on lenny I have dhcp3-server set to ddns (interim) updating bind9.

This works fine as is.

Each recognised host on the network is identified by its mac address - something like:

        host hostname {
                hardware ethernet XX:XX:XX:XX:XX:XX;
                fixed-address 192.168.1.X;
                ddns-hostname "hostname";
        }

(guest hosts get handled via a call to ddns-hostname = binary-to-ascii(10, 8, "-", leased-address); and are not an issue here).

The thing is - for some of the hosts I could really use some CNAME aliases added to DNS.

What I'd like to get is the effect of:

        host hostname {
                hardware ethernet XX:XX:XX:XX:XX:XX;
                fixed-address 192.168.1.X;
                ddns-hostname "hostname";
                ddns-hostname-aliases "alias1, alias2";
        }

Now - I know that ddns-hostname-aliases doesn't exist. Nor have I found anything like this via google - just other people looking for similar solutions.

However, it's the effect I'm trying to achieve here - of adding CNAMEs at the same time as adding an A record - and removing them at DHCP lease expiry.

I see that nsupdate can take a CNAME update.

nsupdate
> update add alias1.domain.tld 3600 IN CNAME hostname.domain.tld
> send

But I can't see any support in the current dhcpd setup for sending this.

Does anyone have any suggestions as to other ways to trigger the update? Perhaps someway to call nsupdate as a kind of trigger on update of dhcp or something?