CNAME record for the root of the domain

[Matt Rowley]

> I wan to point "example.org" to the same ip as "example.com", but I don't want to manually change the A entry when example.com change its address.

Maybe I'm misunderstanding what you're after... but if you're ok with all of the records in the zone being identical, you could point both zones to the same file in your named.conf; you just need to keep it generic by using the @ origin symbol instead of referencing the zone name.  For example,

@		IN SOA	ns.example.com. foo.example.com. (
				2011010101 ; serial
				7200       ; refresh (2 hours)
				3600       ; retry (1 hour)
				604800     ; expire (1 week)
				7200       ; minimum (2 hours)
				)
		IN	NS	ns1.example.org.
		IN	NS	ns2.example.com.
		IN	A	192.168.1.9

www		IN	CNAME	@
...

etc.

--Matt