resolution problem

Matus UHLAR - fantomas uhlar at fantomas.sk
Thu May 19 14:42:16 UTC 2016


>> >colostate.edu.          172800  IN      NS      dns1.colostate.edu.
>> >colostate.edu.          172800  IN      NS      dns3.colostate.edu.
>> >;; Received 119 bytes from 192.41.162.30#53(l.edu-servers.net) in 78 ms
>> >
>> >www.cloudsat.cira.colostate.edu. 3600 IN CNAME  dpc.cira.colostate.edu.
>> >dpc.cira.colostate.edu. 3600    IN      A       129.82.109.62
>> >;; Received 83 bytes from 129.82.103.121#53(dns1.colostate.edu) in 36 ms

>In article <mailman.812.1463666011.73610.bind-users at lists.isc.org>,
> Matus UHLAR - fantomas <uhlar at fantomas.sk> wrote:
>> often a problem of invalid NS delegation, or bad TTL (A record for a server
>> expires before NS record).

On 19.05.16 15:31, Sam Wilson wrote:
>Glue A records for the nameservers have 172800 TTL, authoritative A
>records have 1200.

that's it!

;; ANSWER SECTION:
colostate.edu.          3600    IN      NS      dns3.colostate.edu.
colostate.edu.          3600    IN      NS      dns1.colostate.edu.

;; ADDITIONAL SECTION:
dns3.colostate.edu.     1200    IN      A       129.82.103.111
dns1.colostate.edu.     1200    IN      A       129.82.103.121

after 1200 seconds, the A records expire, but the NS records don't.

Next 2400 seconds you know that you have to ask dns3.colostate.edu and
dns1.colostate.edu, but you can't find their IPs, because ...  you don't
know their IPs.

while some DNS servers can cope with that, it's still broken setup.

-- 
Matus UHLAR - fantomas, uhlar at fantomas.sk ; http://www.fantomas.sk/
Warning: I wish NOT to receive e-mail advertising to this address.
Varovanie: na tuto adresu chcem NEDOSTAVAT akukolvek reklamnu postu.
I feel like I'm diagonally parked in a parallel universe. 


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