TTL on glue records and PTR records
chubirka
chubirka at gwu.edu
Sun Aug 26 16:17:18 UTC 2001
Sorry, but I'm unclear with your response. Are you saying that the TTL for
the parent zone, gwu.edu will affect any/all records in the delegated
subdomain, va.gwu.edu, even though a different TTL has been set for any/all
records in the subdomain? What's the point then? Also, If what you say is
true and my TTL overrides the TTL for any records in the subdomain, why am I
getting such odd numbers for the TTL if the default for my zone is 2 hours?
Why do I get the following output with dig on a query of www.va.gwu.edu from
different nameservers running different versions of BIND for the parent
zone, gwu.edu?
./dig www.va.gwu.edu q-any
; <<>> DiG 9.1.3 <<>> www.va.gwu.edu q-any
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 7904
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 2
;; QUESTION SECTION:
;www.va.gwu.edu. IN A
;; ANSWER SECTION:
www.va.gwu.edu. 86376 IN A 128.164.24.5
;; AUTHORITY SECTION:
va.gwu.edu. 259176 IN NS b.ns.va.gwu.edu.
va.gwu.edu. 259176 IN NS a.ns.va.gwu.edu.
;; ADDITIONAL SECTION:
a.ns.va.gwu.edu. 259176 IN A 128.164.24.4
b.ns.va.gwu.edu. 259176 IN A 128.164.26.1
----------------------------------------------------------------------
# ./dig @ns.gwu.edu q-any www.va.gwu.edu
; <<>> DiG 9.1.3 <<>> @ns.gwu.edu q-any www.va.gwu.edu
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 55907
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0
;; QUESTION SECTION:
;q-any. IN A
;; AUTHORITY SECTION:
. 86400 IN SOA A.ROOT-SERVERS.NET.
hostmaster.n
siregistry.NET. 2001082600 1800 900 604800 86400
;; Query time: 95 msec
;; SERVER: 128.164.141.11#53(ns.gwu.edu)
;; WHEN: Sun Aug 26 11:43:18 2001
;; MSG SIZE rcvd: 99
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 24661
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 2
;; QUESTION SECTION:
;www.va.gwu.edu. IN A
;; ANSWER SECTION:
www.va.gwu.edu. 86400 IN A 128.164.24.5
;; AUTHORITY SECTION:
va.gwu.edu. 259200 IN NS a.ns.va.gwu.edu.
va.gwu.edu. 259200 IN NS b.ns.va.gwu.edu.
;; ADDITIONAL SECTION:
a.ns.va.gwu.edu. 259200 IN A 128.164.24.4
b.ns.va.gwu.edu. 259200 IN A 128.164.26.1
;; Query time: 12 msec
;; SERVER: 128.164.141.11#53(ns.gwu.edu)
;; WHEN: Sun Aug 26 11:43:18 2001
;; MSG SIZE rcvd: 125
----- Original Message -----
From: "Len Conrad" <LConrad at Go2France.com>
To: <bind-users at isc.org>
Sent: Saturday, August 25, 2001 1:58 PM
Subject: Re: TTL on glue records and PTR records
>I'm a parent zone, gwu.edu, and I've been having a discussion with one of
the
>admins of my delegated subdomains, va.gwu.edu, regarding a couple of
issues:
>1. I thought that my zone TTL only affected the glue records of the
delegated
>subdomain, NOT the entire zone.
TTL´s are valid only for the zone they occur in.
> Doesn't the SOA information in the zone file
>of the delegated subdomain set the TTL for all records in the subdomain?
no. And recently the SOA TTL is no longer the zone default TTL nor the
negative-TTL but just the SOA´s TTL.
>2. He has multiple "A" record names pointing to the same IP addresses for
his
>nameservers
As "documentation" records, those NS records in his zone file won´t be
queried by DNS´s following referrals. So the delegation NS records (in
your DNS as parent) will provide the effective TTL´s.
Len
http://MenAndMice.com/DNS-training
http://BIND8NT.MEIway.com : ISC BIND 8.2.4 for NT4 & W2K
http://IMGate.MEIway.com : Build free, hi-perf, anti-abuse mail gateways
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