SOA directives

[Mark Damrose]

"Lord Skeptic" <skepticlord at hotmail.com> wrote in message
news:a80n0g$8ih at pub3.rc.vix.com...
>
> I apologize for the newbie question but I can't find any information on
the
> net.
>
> I have these settings for my domain (my admin set them):
>
>         refresh = 10800 (3 hours)

How often do secondary servers check to see if the primary server has
updated its serial number

>         retry   = 1800 (30 mins)

If the refresh fails, how often to retry the refresh

>         expire  = 3600000 (41 days 16 hours)

If the refresh continues to fail, how long to hold the data before we decide
it is too old to be of any value and discard it.

>         minimum ttl = 259200 (3 days)

Depending on the version, this could be:
the TTL applied to negative responses (i.e. when a requested record does not
exist)
the default TTL applied to all records that don't specify one
or both

>
> What is the meaning for each value?
> Most importantly, which value do the foreign NS lookup to update their
> records for my domain?

I'm not sure exactly what you're asking here.
If you mean Secondary servers, they check the serial number.  If it is
higher than the serial in the SOA they have, they request a transfer of the
entire zone (or only the parts that have changed if you are using Dynamic
DNS).

If you mean other recursive servers which are not in your control, then they
don't really care about the values in the SOA.  External NS request records,
cache them for the amount of time specified in the TTL of that record, and
request them again once that TTL has expired.