[geeks] synchronizing dhcp and bind

[Mike Meredith]

On Sun, 24 Jun 2007 15:22:47 -0400, Charles Shannon Hendrix wrote:
> I have no idea, but this sounds plausible. Maybe NetBSD needs to
> update their man pages. They say it works, but give the caveat of the
> whole thing being subject to change.

I suspect the NetBSD man pages are taken from the ISC man pages, so
it's the job of ISC to update them. Understandably the ISC are a bit
conservative ... after all their code probably handles zillions of
operations per second. I note that the 'ad-hoc' method of ddns updates
has only relatively recently become depreciated; I remember quite a few
years ago making a relatively risky decision to use 'interim' (new
and relatively untested) rather than 'ad-hoc' (well tested, but
incompatible with the new failover support).

When the IETF finally pushes something through the standards process,
ISC dhcpd will support 'standard' which will almost certainly be close
to 'interim'. But we know how slow IETF can be :)

> What's really the difference between managing the IP addresses in
> dhcpd and doing it in bind?

Zone size and manageability. 

On the manageability side, you need to manage the IP addresses in the
dhcp side and the bind side. Using ddns means less work on the bind
side ... it's easy over a span of years for the two to get out of sync.

On the zone size side, if you're using NAT, it's often easy to allocate
very large dynamic address pools which you probably don't want to
create a PTR record for each one in your zone files. 

I haven't looked at tools for managing zone files, but I suspect
they're a lot better at handling complex zone files than big zone files.


> Seems there are far more tools for managing DNS than dhcp...

I suspect there's a lot of glue code creating dhcp configurations from
ISP customer records; there may be more tools for managing DNS records,
but more addresses are probably dns registered with dhcp than with all
those tools.

-- 
Mike Meredith (http://zonky.org/)
 Power corrupts; Powerpoint corrupts absolutely.
 -- Vint Cerf