[dns-operations] Google DNS overriding TTL settings?

[Chris Boyd]

Anyone else seeing this?  Or is it common knowledge I just tripped over?

Was just looking into a DNS issue for a customer and noticed Google's DNS was reporting cache times of 9700+ seconds, despite the zone TTL being 3600 seconds.

First, an authoritative server, then Google's answers.  Yes, I know Google's answer is different from mine, thus the discovery of the different cache time.

--Chris

CLB-MBP:~ clb$ dig @ns1 www.ionadas.com

; <<>> DiG 9.7.3-P3 <<>> @ns1 www.ionadas.com
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 16220
;; flags: qr aa rd; QUERY: 1, ANSWER: 1, AUTHORITY: 3, ADDITIONAL: 3
;; WARNING: recursion requested but not available

;; QUESTION SECTION:
;www.ionadas.com.		IN	A

;; ANSWER SECTION:
www.ionadas.com.	3600	IN	A	208.81.246.11

================================================

CLB-MBP:~ clb$ dig @8.8.8.8 www.ionadas.com

; <<>> DiG 9.7.3-P3 <<>> @8.8.8.8 www.ionadas.com
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 37844
;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;www.ionadas.com.		IN	A

;; ANSWER SECTION:
www.ionadas.com.	9759	IN	CNAME	ionadas.com.
ionadas.com.		9759	IN	A	208.81.246.21


=====================================================


CLB-MBP:~ clb$ dig @8.8.4.4 www.ionadas.com

; <<>> DiG 9.7.3-P3 <<>> @8.8.4.4 www.ionadas.com
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 42188
;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;www.ionadas.com.		IN	A

;; ANSWER SECTION:
www.ionadas.com.	9710	IN	CNAME	ionadas.com.
ionadas.com.		9710	IN	A	208.81.246.21