DNS tutor needed

[Barry Margolin]

In article <a97uj1$l8q at pub3.rc.vix.com>, scratch <wmedia at xtra.co.nz> wrote:
>
>> > $TTL    259200
>>
>> Rather generous default TTL, sound remote server will honour
>> this and cache data for 3 days, great when everything is stable
>> if that is what you want, but whilst setting up.....
>
>Would 43200 be better? Or less?

43200-86400 is a common range.

>
>>
>> > @               IN      SOA     server.my.own.domain.
>my.email.address.
>> > (
>> >                                 20020103015     ; serial
>>
>> This serial is too big, serial number arithmetic leaves just
>> enough room for YYYYMMDDNN, changing these is a pain, but better
>> do it now, then wonder why when you query the serial in future
>> it doesn't show the number you entered.
>
>So whats the best way to change it if its a pain? (I thought YYYYMMDDNNN was
>acceptable......?)

Serial numbers can be up to about 4x10^10, i.e. a maximum of 10 digits.  A
common serial number format is YYYYMMDDNN -- drop one of the N's at the end
and you should be fine.

>> >                                 604800          ; expire        - 7 days
>> >                                 7200 )          ; default_ttl   - 2
>hours
>>
>> 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.

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