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

At 18:06 -0400 6/19/03, Mark Stapp wrote:
>Would this be a reasonable summary of the discussion on this topic?
>
>1. the looseness of the coupling among primary, secondary, and caching dns
>servers makes it unrealistic to guarantee that no query will see stale
>records.  the deployment experience that we have does not indicate that this
>is a problem.

That's certainly true.  My suggestion neglected the fact that a slave 
server could be out of date with respect to a master.  (It's a 
problem less and less though with NOTIFY, but it's a possibility 
still.)

>2. this section of the draft should make the issues about dns ttls and caching
>more explicit, so that it's clearer what the operational consequences of
>'stale' records might be. I'll add text about the benefits to removing
>dhcp-added dns records when leases expire.

Yup.

>3. the simple ttl guidelines that are in the draft are present to give
>implementors (and administrators) some clue about reasonable ranges and
>defaults. the guidelines are meant to help folks avoid hare-brained
>configurations (what Robert calls "minimizing damage"); the guidelines aren't
>intended to provide a guarantee about how long it may be before changes to
>the dns become universally visible.

Yup.

>4. it's not worthwhile to impose new requirements on DHCP servers to put names
>or addresses in limbo in some way for some period of time after leases expire.

Perhaps, I suppose that it isn't DHCP's problem if the DNS has too 
much persistence...;)
-- 
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Edward Lewis                                            +1-703-227-9854
ARIN Research Engineer

...as graceful as a blindfolded bull in a china shop...

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