Query on ignoring additional section returned in replies

[Elias Ahmed Kamal]

Hi guys,

I'm having issues resolving www.fis.com.my. I'm trying to tell fis.com.my that its an issue at their end, but when checking against 8.8.8.8 it resolves fine....so it MUST be a problem with me.

1. Lookups fail, this is clear enough

root at sputnik # dig @localhost www.fis.com.my

; <<>> DiG 9.9.5-P1 <<>> @localhost www.fis.com.my
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 51246
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;www.fis.com.my.                        IN      A

;; Query time: 0 msec
;; SERVER: 127.0.0.1#53(127.0.0.1)
;; WHEN: Wed Nov 18 17:40:58 MYT 2015
;; MSG SIZE  rcvd: 43


2. All of fis.com.my's authoritative nameservers answer and are consistent
   It tells me that www.wip.fis.com.my is a CNAME for www.fis.com.my
   And that wan1-wan4.fis.com.my is the authoritative servers for *.wip.fis.com.my

root at sputnik # dig @ns1.fis.com.my www.fis.com.my

; <<>> DiG 9.9.5-P1 <<>> @ns1.fis.com.my www.fis.com.my
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 33357
;; flags: qr aa rd; QUERY: 1, ANSWER: 1, AUTHORITY: 4, ADDITIONAL: 5
;; WARNING: recursion requested but not available

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;www.fis.com.my.                        IN      A

;; ANSWER SECTION:
www.fis.com.my.         38400   IN      CNAME   www.wip.fis.com.my.

;; AUTHORITY SECTION:
wip.fis.com.my.         38400   IN      NS      wan1.fis.com.my.
wip.fis.com.my.         38400   IN      NS      wan4.fis.com.my.
wip.fis.com.my.         38400   IN      NS      wan3.fis.com.my.
wip.fis.com.my.         38400   IN      NS      wan2.fis.com.my.

;; ADDITIONAL SECTION:
wan1.fis.com.my.        38400   IN      A       202.188.242.130
wan2.fis.com.my.        38400   IN      A       210.19.86.114
wan3.fis.com.my.        38400   IN      A       175.143.6.162
wan4.fis.com.my.        38400   IN      A       219.92.28.106

;; Query time: 8 msec
;; SERVER: 202.188.242.135#53(202.188.242.135)
;; WHEN: Wed Nov 18 17:41:09 MYT 2015
;; MSG SIZE  rcvd: 205


3. I now do a 3rd lookup test against wan1.fis.com.my for www.wip.fis.com.my and get the answers
   BUT, the nameserver is also returning an authority section saying wip.fis.com.my is now served by ns1.wip.fis.com.my
   [Previously I know wip.fis.com.my was served by wan1-wan4.fis.com.my, but now somehow I'm caching ns1.wip.fis.com.my instead]
   [Question: Is it the expected behaviour that this new NS will override the previous NS for wip.fis.com.my? And is there any way to ignore authority/additional answers that I get from replies?]

root at cbj-cdns21 # dig @wan1.fis.com.my www.wip.fis.com.my

; <<>> DiG 9.9.5-P1 <<>> @wan1.fis.com.my www.wip.fis.com.my
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 43777
;; flags: qr aa rd; QUERY: 1, ANSWER: 3, AUTHORITY: 1, ADDITIONAL: 0
;; WARNING: recursion requested but not available

;; QUESTION SECTION:
;www.wip.fis.com.my.            IN      A

;; ANSWER SECTION:
www.wip.fis.com.my.     5       IN      A       175.143.6.165
www.wip.fis.com.my.     5       IN      A       202.188.242.137
www.wip.fis.com.my.     5       IN      A       210.19.86.117

;; AUTHORITY SECTION:
wip.fis.com.my.         3600    IN      NS      ns1.wip.fis.com.my.

;; Query time: 7 msec
;; SERVER: 202.188.242.130#53(202.188.242.130)
;; WHEN: Wed Nov 18 17:44:59 MYT 2015
;; MSG SIZE  rcvd: 102


4. Lo and behold, ns1.wip.fis.com.my doesn't exist! And because of this all my queries for www.fis.com.my are failing. Am I correct?

root at sputnik # dig @wan1.fis.com.my ns1.wip.fis.com.my

; <<>> DiG 9.9.5-P1 <<>> @wan1.fis.com.my ns1.wip.fis.com.my
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 37457
;; flags: qr aa rd; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0
;; WARNING: recursion requested but not available

;; QUESTION SECTION:
;ns1.wip.fis.com.my.            IN      A

;; AUTHORITY SECTION:
wip.fis.com.my.         3600    IN      SOA     ns1.wip.fis.com.my. webmaster. 2015111825 16384 2048 1048576 2560

;; Query time: 6 msec
;; SERVER: 202.188.242.130#53(202.188.242.130)
;; WHEN: Wed Nov 18 17:47:45 MYT 2015
;; MSG SIZE  rcvd: 81

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