Check that www.bnu.edu.cn exists for IPv4 in case we have a typo on the domain name. Use dig to query the local name server (::1).


; <<>> DiG 9.4.1-P1 <<>> +trace +all bnu.edu.cn soa
;; global options:  printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 1813
;; flags: qr ra; QUERY: 1, ANSWER: 13, AUTHORITY: 0, ADDITIONAL: 14

;; QUESTION SECTION:
;.				IN	NS

;; ANSWER SECTION:
.			34644	IN	NS	l.root-servers.net.
.			34644	IN	NS	m.root-servers.net.
.			34644	IN	NS	b.root-servers.net.
.			34644	IN	NS	e.root-servers.net.
.			34644	IN	NS	g.root-servers.net.
.			34644	IN	NS	a.root-servers.net.
.			34644	IN	NS	j.root-servers.net.
.			34644	IN	NS	f.root-servers.net.
.			34644	IN	NS	k.root-servers.net.
.			34644	IN	NS	i.root-servers.net.
.			34644	IN	NS	c.root-servers.net.
.			34644	IN	NS	h.root-servers.net.
.			34644	IN	NS	d.root-servers.net.

;; ADDITIONAL SECTION:
k.root-servers.net.	524162	IN	A	193.0.14.129
k.root-servers.net.	524162	IN	AAAA	2001:7fd::1
a.root-servers.net.	522636	IN	A	198.41.0.4
a.root-servers.net.	522636	IN	AAAA	2001:503:ba3e::2:30
c.root-servers.net.	223294	IN	A	192.33.4.12
d.root-servers.net.	219848	IN	A	128.8.10.90
d.root-servers.net.	219848	IN	AAAA	2001:500:2d::d
j.root-servers.net.	134906	IN	A	192.58.128.30
j.root-servers.net.	134906	IN	AAAA	2001:503:c27::2:30
b.root-servers.net.	480900	IN	A	192.228.79.201
e.root-servers.net.	478220	IN	A	192.203.230.10
i.root-servers.net.	522743	IN	A	192.36.148.17
i.root-servers.net.	522743	IN	AAAA	2001:7fe::53
f.root-servers.net.	523507	IN	A	192.5.5.241

;; Query time: 8 msec
;; SERVER: 127.0.0.1#53(127.0.0.1)
;; WHEN: Thu May 17 12:49:28 2012
;; MSG SIZE  rcvd: 512

;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 1068
;; flags: qr; QUERY: 1, ANSWER: 0, AUTHORITY: 6, ADDITIONAL: 8

;; QUESTION SECTION:
;bnu.edu.cn.			IN	SOA

;; AUTHORITY SECTION:
cn.			172800	IN	NS	a.dns.cn.
cn.			172800	IN	NS	c.dns.cn.
cn.			172800	IN	NS	e.dns.cn.
cn.			172800	IN	NS	ns.cernet.net.
cn.			172800	IN	NS	b.dns.cn.
cn.			172800	IN	NS	d.dns.cn.

;; ADDITIONAL SECTION:
a.dns.cn.		172800	IN	A	203.119.25.1
b.dns.cn.		172800	IN	A	203.119.26.1
c.dns.cn.		172800	IN	A	203.119.27.1
d.dns.cn.		172800	IN	A	203.119.28.1
e.dns.cn.		172800	IN	A	203.119.29.1
ns.cernet.net.		172800	IN	A	202.112.0.44
a.dns.cn.		172800	IN	AAAA	2001:dc7::1
d.dns.cn.		172800	IN	AAAA	2001:dc7:1000::1

;; Query time: 124 msec
;; SERVER: 2001:dc3::35#53(m.root-servers.net)
;; WHEN: Thu May 17 12:49:28 2012
;; MSG SIZE  rcvd: 291

;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 1836
;; flags: qr; QUERY: 1, ANSWER: 0, AUTHORITY: 5, ADDITIONAL: 2

;; QUESTION SECTION:
;bnu.edu.cn.			IN	SOA

;; AUTHORITY SECTION:
edu.cn.			172800	IN	NS	dns.edu.cn.
edu.cn.			172800	IN	NS	ns2.cuhk.hk.
edu.cn.			172800	IN	NS	ns2.cernet.net.
edu.cn.			172800	IN	NS	dns2.edu.cn.
edu.cn.			172800	IN	NS	deneb.dfn.de.

;; ADDITIONAL SECTION:
dns.edu.cn.		172800	IN	A	202.112.0.35
dns2.edu.cn.		172800	IN	A	202.112.0.13

;; Query time: 164 msec
;; SERVER: 202.112.0.44#53(ns.cernet.net)
;; WHEN: Thu May 17 12:49:28 2012
;; MSG SIZE  rcvd: 176

;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 728
;; flags: qr; QUERY: 1, ANSWER: 0, AUTHORITY: 2, ADDITIONAL: 2

;; QUESTION SECTION:
;bnu.edu.cn.			IN	SOA

;; AUTHORITY SECTION:
bnu.edu.cn.		172800	IN	NS	NS.bnu.edu.cn.
bnu.edu.cn.		172800	IN	NS	NS2.bnu.edu.cn.

;; ADDITIONAL SECTION:
NS.bnu.edu.cn.		172800	IN	A	202.112.80.106
NS2.bnu.edu.cn.		172800	IN	A	202.112.81.130

;; Query time: 160 msec
;; SERVER: 202.112.0.35#53(dns.edu.cn)
;; WHEN: Thu May 17 12:49:28 2012
;; MSG SIZE  rcvd: 95

;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 696
;; flags: qr aa; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 2

;; QUESTION SECTION:
;bnu.edu.cn.			IN	SOA

;; ANSWER SECTION:
bnu.edu.cn.		10800	IN	SOA	ns.bnu.edu.cn. info.bnu.edu.cn. 2012051642 10800 3600 604800 10800

;; AUTHORITY SECTION:
bnu.edu.cn.		10800	IN	NS	ns2.bnu.edu.cn.
bnu.edu.cn.		10800	IN	NS	ns.bnu.edu.cn.

;; ADDITIONAL SECTION:
ns.bnu.edu.cn.		10800	IN	A	202.112.80.106
ns2.bnu.edu.cn.		10800	IN	A	202.112.80.168

;; Query time: 387 msec
;; SERVER: 202.112.80.106#53(NS.bnu.edu.cn)
;; WHEN: Thu May 17 12:49:30 2012
;; MSG SIZE  rcvd: 136

HTTP

Looking for CNAME of www.bnu.edu.cn
Checking if there is a AAAA for www.bnu.edu.cn ... FAILED.


; <<>> DiG 9.4.1-P1 <<>> www.bnu.edu.cn aaaa
;; global options:  printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 543
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0

;; QUESTION SECTION:
;www.bnu.edu.cn.			IN	AAAA

;; AUTHORITY SECTION:
bnu.edu.cn.		10800	IN	SOA	ns.bnu.edu.cn. info.bnu.edu.cn. 2012051642 10800 3600 604800 10800

;; Query time: 4 msec
;; SERVER: 127.0.0.1#53(127.0.0.1)
;; WHEN: Thu May 17 12:49:30 2012
;; MSG SIZE  rcvd: 76

Checking other options ... succeeded as ipv6.bnu.edu.cn.
Sending...

HEAD / HTTP/1.1
Host: ipv6.bnu.edu.cn
User-Agent: ipv6-survey.pl/1.97 http://www.mrp.net/IPv6_Survey.html

Reading ...

HTTP/1.1 200 OK
Date: Thu, 17 May 2012 03:19:32 GMT
Server: Apache/2.2.3 (Red Hat)
Last-Modified: Fri, 29 Oct 2010 02:09:58 GMT
ETag: "1e2878e-ad-f48ca980"
Accept-Ranges: bytes
Content-Length: 173
Connection: close
Content-Type: text/html; charset=GB2312

Accessed / [2001:da8:207:e180:21a:64ff:fe6d:d1eb] Response: HTTP/1.1 200 OK

SMTP

MX 5 email.bnu.edu.cn
Looking for AAAA on email.bnu.edu.cn
MX 5 email1.bnu.edu.cn
Looking for AAAA on email1.bnu.edu.cn
MX 5 email2.bnu.edu.cn
Looking for AAAA on email2.bnu.edu.cn

DNS

Looking for AAAA of NS NS.bnu.edu.cn
No AAAA record for NS.bnu.edu.cn
Looking for AAAA of NS ns2.bnu.edu.cn
No AAAA record for ns2.bnu.edu.cn

NTP

Looking for an A record for ntp.bnu.edu.cn
Looking for an A record for clock.bnu.edu.cn
Looking for an A record for time.bnu.edu.cn
Found an A or AAAA record. Now looking for a AAAA.
Cannot find a AAAA record for time.bnu.edu.cn
Cannot find a AAAA record for time.ipv6.bnu.edu.cn

XMPP

Looking for a SRV record for _xmpp-client._tcp.bnu.edu.cn
Looking for a SRV record for _xmpp-server._tcp.bnu.edu.cn

Last Updated: Thu May 17 03:19:34 2012 UTC