Re: DNS primer

[Philip Rowlands <[EMAIL PROTECTED]>]

On Mon, 8 Nov 2004, Dave Howe wrote:

>linuxops.net.  38400  IN  SOA  ns1.linuxops.net. hostmaster.linuxops.net. (
>         2004091902  ; Serial
>         28800  ; Refresh (8 hours)
>         7200  ; Retry (2 hours)
>         604800  ; ExpTTLire (7 days)
>         86400 )  ; TTL (24 hours)
>
> > 86400 )  ; TTL (24 hours)
>record expiry for caches

I wish this comment "TTL" would vanish from the default zonefiles of the
world... The fifth field in SOA is the negative-cache TTL; the time that
a lookup failure can be remembered and replayed without recourse to an
authoritative server.

See RFC2308, and please test against your favourite caching server.
google.com is a good test-case - ncache TTL is set to 60 seconds.


Cheers,
Phil