DNS tutor needed

[Barry Margolin]

In article <a9euqa$5ks at pub3.rc.vix.com>,
Simon Waters  <Simon at wretched.demon.co.uk> wrote:
>
>Barry Margolin wrote:
>> 
>> >> That's negative TTL not default.
>> >
>> >Sorry?
>> 
>> Since BIND 8, the last field in the SOA record has been the TTL of negative
>> caching, not the default TTL.  The $TTL directive sets the default TTL.
>
>And as I have pointed out before, BIND still defaults to using
>the last field of the SOA as a default TTL if no $TTL directive
>exists.

But since the OP clearly has $TTL statements, this is irrelevant.  The
comment in his SOA record was not correct because of this.

>This appears to contradict the RFC that says NOT TO USE the last
>field of the SOA as the default TTL. 

Sometimes backward compatibility is more important than standards
compliance.  Complying with the standard would cause lots of problems for
sites that upgrade.

>It is a minor point, but the RFC appears to prefer a default
>like 86400 seconds for default TTL, over the actual behaviour of
>BIND. The main result is many people still overload the last
>field of the SOA, and use either an inappropriately high
>negative TTL, or an inappropriately low default TTL.

And that's why BIND complains in the log about it -- to let them know that
they should fix their zone files.

-- 
Barry Margolin, barmar at genuity.net
Genuity, Woburn, MA
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