two questions regarding dynamic dns updates

Martin McCormick martin at
Thu Mar 23 19:47:22 UTC 2006

"David W. Hankins" writes:
>Of course this is documented as optional, and I can't recall which we're
>currently implementing in 3.0.x.  I suspect it's NXDOMAIN (but the
>code intentionally waffles).
>Which means I doubt this actually works unless you make the updates for
>additional records while the client is bound to the address, and remove
>them afterwards (before gaining forward binding again).
>Which probably means participating in client updates.

	I remember a couple of years or so ago, I had a CNAME or alias
bound to the name of a host with a dynamic dhcp lease.  If I remember
right, this caused a problem that disallowed dhcpd from removing that
A record.  I remember thinking that one couldn't have a CNAME like CNAME'd to this dynamic lease which could then go
from one VLAN to another on campus and be accessible via that alias
even though the alias always points to the name in an A record.

	I think in our case, we weren't trying to come up with a
resource that moved all over the place, but had a change of computer
with the new one unable to register properly until I removed the CNAME.

	It would seem to me that no great harm would be done by
letting the name come and go on whatever network they showed up on
and, when somebody used the alias, they would either get connected if
that host was on or get a "host not found" condition if it wasn't
anywhere on our network.  That's basically what you get in the world
of dynamic leases anyway when somebody's lease expires.

Martin McCormick WB5AGZ  Stillwater, OK 
Systems Engineer
OSU Information Technology Department Network Operations Group

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