Re: [dhcwg] DDNS-DHCP [6]: Relationship between DNS TTL and DHCP lease length

    Date:        Thu, 19 Jun 2003 21:03:52 -0400
    From:        Michael Richardson <mcr@sandelman.ottawa.on.ca>
    Message-ID:  <200306200103.h5K13rWl030720@sandelman.ottawa.on.ca>

First, Mark's summary looked fine to me.

But ...

  | As such, what I really want is a dynamic update operation which actually
  | says "install this record with TTL=XXX, deleting the record after YYY"
  | (Clearly, XXX < YYY, and some may argue YYY:=XXX. I'm undecided)

The XXX & YYY relationship isn't important here but XXX << YYY (in the
mathematical << sense, not "shift left") if this were to have any hope
of working.

But yes, that's what almost everyone wanted when dynamic update was
being defined - and a lot of effort was spend attempting to find
something which would actually work like that.   Unfortunately,
nothing reliable could be found, so that is not what exists.

You can try and dream up a protocol to allow this to work, but
first please go and review all the archives from when dynamic
update was being designed, and then again since then whenever anyone
has suggested it since - it is not nearly as simple to make work
properly as it seems it should be - and if it can't be guaranteed
to work, then the host has to deal with it other ways anyway.

  | I have really no problem sending a new update every couple of minutes.
  | In fact, I'd prefer to do this.

Unfortunately, by itself, that doesn't help - that was the original
plan for this (you need to investigate the way the whole DNS works,
including the primary/secondary relationship, and servers that crash at
inconvenient times, to see the problems).

kre

_______________________________________________
dhcwg mailing list
dhcwg@ietf.org
https://www1.ietf.org/mailman/listinfo/dhcwg