TTLs

[Fabiola Caceres]

All,
please forgive me for my question. I have read the list and the book, but
I'm still NOT clear of how "this" new TTL work and what is the meaning of
the negative TTL , whta does it do?

Here is one of my zone file right before I changed the TTL to 900 sec:
<using dig>

>dig SAO vh4.infi.net

; <<>> DiG 8.3 <<>> SAO vh4.infi.net
;; res options: init recurs defnam dnsrch
;; got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 4
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0
;; QUERY SECTION:
;;      vh4.infi.net, type = A, class = IN

;; AUTHORITY SECTION:
vh4.infi.net.           1D IN SOA       ns1.infi.net. hostmaster.infi.net.
(
                                        2001062200      ; serial
                                        3H              ; refresh
                                        1H              ; retry
                                        1W              ; expiry
                                        1D )            ; minimum


;; Total query time: 18 msec
;; FROM: ns1.infi.net to SERVER: default -- 209.97.61.10
;; WHEN: Mon Jul 16 14:32:03 2001
;; MSG SIZE  sent: 30  rcvd: 81
----------------------------------

NOW, here is the same zone file, but after I reload my name server:
>dig SAO vh4.infi.net

; <<>> DiG 8.3 <<>> SAO vh4.infi.net
;; res options: init recurs defnam dnsrch
;; got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 4
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0
;; QUERY SECTION:
;;      vh4.infi.net, type = A, class = IN

;; AUTHORITY SECTION:
vh4.infi.net.           1D IN SOA       ns1.infi.net. hostmaster.infi.net.
(
                                        2001071400      ; serial
                                        3H              ; refresh
                                        1H              ; retry
                                        1W              ; expiry
                                        1D )            ; minimum


;; Total query time: 3 msec
;; FROM: ns1.infi.net to SERVER: default -- 209.97.61.10
;; WHEN: Mon Jul 16 14:32:18 2001
;; MSG SIZE  sent: 30  rcvd: 81

The only difference I see it's the serial number change, but not the TTL
lower to 15 min (900 sec)

Here is the zone file:
$TTL 900
@ IN SOA ns1.infi.net. hostmaster.infi.net. (
        2001071400      ; Serial
        10800           ; Refresh after 3 hours
        3600            ; Retry after 1 hour
        604800          ; Expire after 1 week
        86400           ; Minimum TTL of 1 day
)
        IN      NS      ns1.infi.net.
        IN      NS      ns2.infi.net.
        IN      NS      ns3.infi.net.
        IN      NS      ns4.infi.net.
vh40000 IN      A       216.33.107.83
vh40001 IN      A       216.33.107.84
-----------------------------------------
Please advise.

Fabiola Caceres
Hostmaster and Systems Administrator
InfiNet Systems Group
fabiola at infi.net
(757)624-2284