TTL's in 8.3

[Michael Barber]

I've got the O'reilly, 4th edition and I've read pg211-213 6 times... I am
time pressed to get this fixed so I apologize if I'm missing a search or a
book that has a better explanation.  I'm trying to get up to speed as
quickly as possible with the mess I've been handed.

It appears that the TTL options in 8.3 have increased dramatically and the
person that set up these zone files look like they have made this overly
complex and were more lost than I am.  I've got an example zone file
below....

1.  I don't see the $ttl setting anywhere.  I think Bill said earlier this
should be set in 8.2 or greater or you get a warning...and I don't see a
warning in my event logs???  In any case, where do I set this anywhere-a
single line on top, anywhere?

; TTL for this zone
$TTL 18000

2.  It seems to be an explicit TTL of 1800 has been set for every single
record in every single zone file I have (gosh what a mess I'm thinking).
This does not have to be the case right?  Tell me I can get rid of all those
1800's and maybe use the $ttl on top of the zone if necessary.  1800 is too
small anyway !!!!!  Can I get rid of ALL of them including the one 1800 IN
SOA and 1800 IN NS  ?

3.  If this is correct and the 1800 at the end of the SOA is the negative
caching TTL....and there is no $ttl explicit defined....than what is the ttl
that this example zone file is using -- is it the 1800 IN SOA ?

4.  Is there a TTL precedence...its not well written in the BIND book...  My
guess is that it is

$ttl > explicit TTL on SOA > explicit TTL on individual resource records.


; BIND version named 8.4.4 Fri Jan 16 22:45:44 2004
; BIND version marka at drugs:src/port/winnt
; zone 'comcity.us'   first transfer
; from [209.66.93.2].53:53 (local [209.10.62.22].1046) using AXFR at Mon Mar
08 13:59:21 2004
; NOT TSIG verified
$ORIGIN us.
comcity 1800 IN SOA ns.comcity.com. webmaster.comcity.com. (
  2004030801 43200 7200 604800 1800 )
 1800 IN NS ns.comcity.com.
 1800 IN NS ns2.comcity.com.
 1800 IN MX 10 mail.comcity.us.
 1800 IN A 209.66.93.2
$ORIGIN comcity.us.
ftp 1800 IN A 209.66.93.2
mail 1800 IN A 209.66.93.2
localhost 1800 IN A 127.0.0.1
www 1800 IN A 209.66.93.2

Thank You very much.
Michael