[dns-operations] Usage of dns query negative cache

Stephane Bortzmeyer bortzmeyer at nic.fr
Thu Sep 3 13:05:26 UTC 2015 

On Thu, Sep 03, 2015 at 12:32:05AM -0700,
 Grant Ridder <shortdudey123 at gmail.com> wrote 
 a message of 42 lines which said:

> It appears Google [...] don't do this on their public DNS servers,

Are you sure? I feel the opposite (see the RTT on these two
consecutive requests):

% dig @8.8.4.4 A doesnotexist.bortzmeyer.org

; <<>> DiG 9.10.2-P4 <<>> @8.8.4.4 A doesnotexist.bortzmeyer.org
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 48677
;; flags: qr rd ra ad; QUERY: 1, ANSWER: 0, AUTHORITY: 8, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags: do; udp: 512
;; QUESTION SECTION:
;doesnotexist.bortzmeyer.org. IN	A

;; AUTHORITY SECTION:
ha22li1tlogga3v2cs2q2lfte919ebng.bortzmeyer.org. 3599 IN NSEC3 1 0 5 58D1D9F5C0D28847 (
				NE6D89M2CTPEB8IF90Q1V9OGNLH3DSDI
				A RRSIG )
ha22li1tlogga3v2cs2q2lfte919ebng.bortzmeyer.org. 3599 IN RRSIG NSEC3 8 3 3600 (
				20150920004157 20150830210756 53605 bortzmeyer.org.
				WkDXK6ezp75TIHrif+V5x64o1Jnre4r6beBDXx29j05Y
				mmkJM+COIJ8WWyOQlo26y+XT3G+20fiyylQBAsPvNNKJ
				0G6JrrHHoTvpQeeNJVPrhKx6tx0NDBkMNGULIN0m3Cvp
				zpq660h5VtjHpkTOeMZf1zjfJzMDDtBpd3r0/FE= )
q27s9fq01r10fnkab9il2k0g06a876h4.bortzmeyer.org. 3599 IN NSEC3 1 0 5 58D1D9F5C0D28847 (
				SG943UTGIOKSS6VS12LC09GQR70I32T8
				A NS SOA MX TXT AAAA RRSIG DNSKEY NSEC3PARAM )
q27s9fq01r10fnkab9il2k0g06a876h4.bortzmeyer.org. 3599 IN RRSIG NSEC3 8 3 3600 (
				20150918094728 20150830010756 53605 bortzmeyer.org.
				gjE5KOz5RWK6PrrzZCL5Zrsaw4aLe6dxOnYJUOgKp9Dt
				liG6F5IkZPXkouXuaNSsMPTdrdugkBDlR5inIiHe5gyg
				/JTn9X8WgwxKo1Ys/5hkuvD3b3otPreU3x5pdXqyd4fb
				pbzFI/SGcBTo2rNEyAe/FOVw5odd/HOQHMYxa+A= )
133etqqcdu75lfhtgbk4f855cmi1qth5.bortzmeyer.org. 3599 IN NSEC3 1 0 5 58D1D9F5C0D28847 (
				A6E41OM8MHBNM5QM9L4CIHPE8B7V97EE
				A RRSIG )
133etqqcdu75lfhtgbk4f855cmi1qth5.bortzmeyer.org. 3599 IN RRSIG NSEC3 8 3 3600 (
				20150918115709 20150829130756 53605 bortzmeyer.org.
				i+BL1zWyeHa43x2XebP98g9giEqoIfdIOByK27VHh1FE
				oiQAHtkmG9idqhiUdXAMlGh5u1r04mVdLk/YX2xixbtq
				F8COAum+33+PkB1wt2rEqURXsad8LCmwvG3xItQu+Px/
				A3PM+siI/bkp5zIdBwlq6xuIRQir1ruoo3BPTdc= )
bortzmeyer.org.		1799 IN	SOA ns3.bortzmeyer.org. hostmaster.bortzmeyer.org. (
				2015090100 ; serial
				7200       ; refresh (2 hours)
				3600       ; retry (1 hour)
				604800     ; expire (1 week)
				3600       ; minimum (1 hour)
				)
bortzmeyer.org.		1799 IN	RRSIG SOA 8 2 3600 (
				20150921115314 20150901010756 53605 bortzmeyer.org.
				eOQNASbVZgzlU4x1ChaAZwG9Gj+CFRhDtVzT3vx2nqlN
				+d2Q58hk3wZcb1dTyrSTHCZK8EyEt4/rxkMY0WuDzIeE
				nH8yEeV5uyr32EY7a6JfFQBDpQ2sFRXDm2+/CRZkMSwi
				lHJ/uCkoLZGCTHcMnC/hBrf6ykux9PnrO61p2No= )

;; Query time: 121 msec
;; SERVER: 8.8.4.4#53(8.8.4.4)
;; WHEN: Thu Sep 03 13:02:11 UTC 2015
;; MSG SIZE  rcvd: 1065



% dig @8.8.4.4 A doesnotexist.bortzmeyer.org

; <<>> DiG 9.10.2-P4 <<>> @8.8.4.4 A doesnotexist.bortzmeyer.org
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 11802
;; flags: qr rd ra ad; QUERY: 1, ANSWER: 0, AUTHORITY: 8, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags: do; udp: 512
;; QUESTION SECTION:
;doesnotexist.bortzmeyer.org. IN	A

;; AUTHORITY SECTION:
ha22li1tlogga3v2cs2q2lfte919ebng.bortzmeyer.org. 3565 IN NSEC3 1 0 5 58D1D9F5C0D28847 (
				NE6D89M2CTPEB8IF90Q1V9OGNLH3DSDI
				A RRSIG )
ha22li1tlogga3v2cs2q2lfte919ebng.bortzmeyer.org. 3565 IN RRSIG NSEC3 8 3 3600 (
				20150920004157 20150830210756 53605 bortzmeyer.org.
				WkDXK6ezp75TIHrif+V5x64o1Jnre4r6beBDXx29j05Y
				mmkJM+COIJ8WWyOQlo26y+XT3G+20fiyylQBAsPvNNKJ
				0G6JrrHHoTvpQeeNJVPrhKx6tx0NDBkMNGULIN0m3Cvp
				zpq660h5VtjHpkTOeMZf1zjfJzMDDtBpd3r0/FE= )
q27s9fq01r10fnkab9il2k0g06a876h4.bortzmeyer.org. 3565 IN NSEC3 1 0 5 58D1D9F5C0D28847 (
				SG943UTGIOKSS6VS12LC09GQR70I32T8
				A NS SOA MX TXT AAAA RRSIG DNSKEY NSEC3PARAM )
q27s9fq01r10fnkab9il2k0g06a876h4.bortzmeyer.org. 3565 IN RRSIG NSEC3 8 3 3600 (
				20150918094728 20150830010756 53605 bortzmeyer.org.
				gjE5KOz5RWK6PrrzZCL5Zrsaw4aLe6dxOnYJUOgKp9Dt
				liG6F5IkZPXkouXuaNSsMPTdrdugkBDlR5inIiHe5gyg
				/JTn9X8WgwxKo1Ys/5hkuvD3b3otPreU3x5pdXqyd4fb
				pbzFI/SGcBTo2rNEyAe/FOVw5odd/HOQHMYxa+A= )
133etqqcdu75lfhtgbk4f855cmi1qth5.bortzmeyer.org. 3565 IN NSEC3 1 0 5 58D1D9F5C0D28847 (
				A6E41OM8MHBNM5QM9L4CIHPE8B7V97EE
				A RRSIG )
133etqqcdu75lfhtgbk4f855cmi1qth5.bortzmeyer.org. 3565 IN RRSIG NSEC3 8 3 3600 (
				20150918115709 20150829130756 53605 bortzmeyer.org.
				i+BL1zWyeHa43x2XebP98g9giEqoIfdIOByK27VHh1FE
				oiQAHtkmG9idqhiUdXAMlGh5u1r04mVdLk/YX2xixbtq
				F8COAum+33+PkB1wt2rEqURXsad8LCmwvG3xItQu+Px/
				A3PM+siI/bkp5zIdBwlq6xuIRQir1ruoo3BPTdc= )
bortzmeyer.org.		1765 IN	SOA ns3.bortzmeyer.org. hostmaster.bortzmeyer.org. (
				2015090100 ; serial
				7200       ; refresh (2 hours)
				3600       ; retry (1 hour)
				604800     ; expire (1 week)
				3600       ; minimum (1 hour)
				)
bortzmeyer.org.		1765 IN	RRSIG SOA 8 2 3600 (
				20150921115314 20150901010756 53605 bortzmeyer.org.
				eOQNASbVZgzlU4x1ChaAZwG9Gj+CFRhDtVzT3vx2nqlN
				+d2Q58hk3wZcb1dTyrSTHCZK8EyEt4/rxkMY0WuDzIeE
				nH8yEeV5uyr32EY7a6JfFQBDpQ2sFRXDm2+/CRZkMSwi
				lHJ/uCkoLZGCTHcMnC/hBrf6ykux9PnrO61p2No= )

;; Query time: 20 msec
;; SERVER: 8.8.4.4#53(8.8.4.4)
;; WHEN: Thu Sep 03 13:02:14 UTC 2015
;; MSG SIZE  rcvd: 1065

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