Strange resolver behavior

[Xin LI]

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Hi,

It looks like that certain (mis)configuration by the baidu.com DNS
administrators has caused this, but I have no clue why our resolver
would return NXDOMAIN after it gets a positive response?  (Yes, I know
that _ is not appropriate for domain names :)

[delphij at charlie] ~> host -a dict.baidu.com
Trying "dict.baidu.com"
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 59711
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 4, ADDITIONAL: 0

;; QUESTION SECTION:
;dict.baidu.com.			IN	ANY

;; ANSWER SECTION:
dict.baidu.com.		7153	IN	CNAME	ps_other.a.shifen.com.

;; AUTHORITY SECTION:
baidu.com.		159107	IN	NS	ns4.baidu.com.
baidu.com.		159107	IN	NS	ns2.baidu.com.
baidu.com.		159107	IN	NS	ns3.baidu.com.
baidu.com.		159107	IN	NS	dns.baidu.com.

Received 136 bytes from 127.0.0.1#53 in 31 ms
[delphij at charlie] ~> host -a ps_other.a.shifen.com
Trying "ps_other.a.shifen.com"
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 64825
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 4, ADDITIONAL: 0

;; QUESTION SECTION:
;ps_other.a.shifen.com.		IN	ANY

;; ANSWER SECTION:
ps_other.a.shifen.com.	1113	IN	A	202.108.22.46

;; AUTHORITY SECTION:
a.shifen.com.		72679	IN	NS	ns3.a.shifen.com.
a.shifen.com.		72679	IN	NS	ns2.a.shifen.com.
a.shifen.com.		72679	IN	NS	ns4.a.shifen.com.
a.shifen.com.		72679	IN	NS	ns1.a.shifen.com.

Received 127 bytes from 127.0.0.1#53 in 0 ms
[delphij at charlie] ~> host ps_other.a.shifen.com
ps_other.a.shifen.com has address 202.108.22.46
Host ps_other.a.shifen.com not found: 3(NXDOMAIN)

Cheers,
- --
Xin LI <delphij at delphij.net>	http://www.delphij.net/
FreeBSD - The Power to Serve!
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