Question about this site web.da-us.citibank.com with ttl = 0

[Mark Andrews]

> Is AAAA record mandatory?

	No.  But consistantly responding to queries other than A queries
	is.  RFC 1034 / RFC 1035 describe how to respond to queries for
	types you don't know about or don't have.  RFC 1034 / RFC 1035
	are the base DNS specifications.  There is no justifiable reason
	for any DNS server to get this wrong.

	The nameserver for web.da-us.citibank.com is not RFC 1034 / RFC 1035
	compliant.

> How does it cause problem like I described?

	This will cause the server to be marked as lame.

dig aaaa web.da-us.citibank.com @3dns-c.citibankonline.com +norec

; <<>> DiG 9.3.2 <<>> aaaa web.da-us.citibank.com @3dns-c.citibankonline.com +norec
; (1 server found)
;; global options:  printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 4624
;; flags: qr ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;web.da-us.citibank.com.                IN      AAAA

;; Query time: 245 msec
;; SERVER: 192.193.183.40#53(192.193.183.40)
;; WHEN: Wed Mar 29 10:24:29 2006
;; MSG SIZE  rcvd: 40

	As will this.

; <<>> DiG 9.3.2 <<>> txt web.da-us.citibank.com @3dns-c.citibankonline.com +norec
; (1 server found)
;; global options:  printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 60858
;; flags: qr ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;web.da-us.citibank.com.		IN	TXT

;; Query time: 249 msec
;; SERVER: 192.193.183.40#53(192.193.183.40)
;; WHEN: Wed Mar 29 10:27:08 2006
;; MSG SIZE  rcvd: 40


; <<>> DiG 9.3.2 <<>> a web.da-us.citibank.com @3dns-c.citibankonline.com +norec
; (1 server found)
;; global options:  printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 49960
;; flags: qr aa; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;web.da-us.citibank.com.		IN	A

;; ANSWER SECTION:
web.da-us.citibank.com.	0	IN	A	192.193.187.60

;; Query time: 241 msec
;; SERVER: 192.193.183.40#53(192.193.183.40)
;; WHEN: Wed Mar 29 10:36:01 2006
;; MSG SIZE  rcvd: 56


--
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: Mark_Andrews at isc.org