TTL?

[Len Conrad]

>Im getting a little confused looking at the BIND8 book of O'Reilly. It
>says that the 5th field of the SOA record is the TTL but why now you at
>the list refers to de time to live as $TTL? What difference have  the
>$TTL directive and the field of the SOA record?

$TTL default applies to all RR´s that don´t have explicit TTL. Explicit RR 
TTL override the default

The last field of the SOA is the "m-ttl", which meant originally "minimum 
TTL" but whose current usuage is now "negative TTL".  ie, how long the most 
recent BIND8, 9 cache a negative answer for the zone.

IIRC, the hard maximum for "n-TTL" is 3H.

Len



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