DNS migration and folks that don't play nice

[Ben Scott]

On 4/10/06, Cole Tuininga <colet at code-energy.com> wrote:
>> Unfortunately, shortening the TTL doesn't work for clients (like AOL)
>> that cache/maintain their own DNS.
>
> I was curious - how do folks in general deal with this?

  There's nothing much you can do about Internet brain damage, so all
you can do is plan for it.

  When it comes to service migration, there are usually things one can
do to work around any TTL issues.  These are a good idea even without
deliberate brain damage -- accidental brain damage is common enough. 
For example, when it comes to migrating mail, we're going to implement
a mechanism where the old system forwards mail to the new for some
time after changing the MX records.  We can monitor logs to see how
things progress.

  If think DNS TTL brain damage is bad, try path MTU discovery some time...

> While AOL can certainly constitute a large number of users, my
> inclination is to say "hell with 'em".

  Me too.  Alas, I've found a large number of paying customers either
use AOL themselves, or have customers who do.

  AOL claims their resolvers properly honor TTL
(http://dns.info.aol.com/).  I don't know if one should believe them
or not.  It may have been a "past behavior" thing.  OTOH, AOL is big
enough and incompetent enough that they might think they are doing
things right but still have non-compliant resolvers.

> If they can't conform to proper netiquette, why should
> I be bending over backwards to support them?

  With AOL, it's usually more like bending over forwards...

-- Ben