Re: [Savannah-hackers] Re: DNS Refresh for gnu.org

[Joel N. Weber II]

   Joel N. Weber II writes:
    > Please do an ls -ltr in /var/log and then tail whatever log has
    > changed most recently right after you restart the nameserver, to make
    > sure it likes whatever TTL you pick.

           How can I figure out what is the TTL in the /etc/bind/gnu.org
   file ?

This is the SOA record:

gnu.org.        3600 IN SOA     ns1.gnu.org. hostmaster.gnu.org. (
                                        2001052602      ; Serial
                                        3600            ; Refresh
                                        300             ; Retry
                                        3600000         ; Expire
                                        600 )           ; Minimum

The refresh indicates how often the slaves will try to update the zone
from the master.  The retry indicates how soon they will retry if the
master happened to be inaccessible.  The expire is how long it will
take a slave to decide the data is invalid if it cannot contact the
master.  The minimum is the minimum TTL, which indicates how long it
will take for a caching nameserver at some random site on the internet
to forget whatever data it got.

(I don't exactly understand why it's called the ``minimum TTL'';
perhaps someone else can explain.)

The whole thing about having both a refresh and retry also strikes me
as silly, but that's the way DNS works.

All these times are in seconds.

I just reduced the minimum TTL to 10 minutes, and the nameserver
didn't complain, so we can leave it that way for now.