Ubuntu server 14.04 cannot reach dns but can ping

The server A has access to the Internet, since I get correct response when I use curl . And I have another server B which is free of this issue, of which /etc/network/interfaces and /etc/resolv.conf are the same(except ipaddress, netmask,gateway, both of them are configured with static ip, but in different places).

The output for ping:

Server A:

ping -c3 166.111.8.28
PING 166.111.8.28 (166.111.8.28) 56(84) bytes of data.
64 bytes from 166.111.8.28: icmp_seq=1 ttl=57 time=0.567 ms
64 bytes from 166.111.8.28: icmp_seq=2 ttl=57 time=0.443 ms
64 bytes from 166.111.8.28: icmp_seq=3 ttl=57 time=0.449 ms

--- 166.111.8.28 ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 1999ms
rtt min/avg/max/mdev = 0.443/0.486/0.567/0.059 ms

Server B:

ping -c3 166.111.8.28
PING 166.111.8.28 (166.111.8.28) 56(84) bytes of data.
64 bytes from 166.111.8.28: icmp_seq=1 ttl=60 time=0.323 ms
64 bytes from 166.111.8.28: icmp_seq=2 ttl=60 time=0.506 ms
64 bytes from 166.111.8.28: icmp_seq=3 ttl=60 time=0.517 ms

--- 166.111.8.28 ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 1999ms
rtt min/avg/max/mdev = 0.323/0.448/0.517/0.092 ms

The output for nslookup:

Server A:

> server 166.111.8.28
Default server: 166.111.8.28
Address: 166.111.8.28#53
> info.tsinghua.edu.cn
;; connection timed out; no servers could be reached

Server B:

> server 166.111.8.28
Default server: 166.111.8.28
Address: 166.111.8.28#53
> info.tsinghua.edu.cn
Server:     166.111.8.28
Address:    166.111.8.28#53

Name:   info.tsinghua.edu.cn
Address: 166.111.4.98

166.111.8.28 is the dns server

=====(update)

ufw is inactive, and no rules in iptables.

dig -x 127.0.0.1 output:

Server A:

; <<>> DiG 9.9.5-3ubuntu0.1-Ubuntu <<>> -x 127.0.0.1
;; global options: +cmd
;; connection timed out; no servers could be reached

Server B:

; <<>> DiG 9.9.5-3ubuntu0.2-Ubuntu <<>> -x 127.0.0.1
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 64593
;; flags: qr rd ra ad; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 512
;; QUESTION SECTION:
;1.0.0.127.in-addr.arpa.        IN  PTR

;; AUTHORITY SECTION:
in-addr.arpa.       1248    IN  SOA b.in-addr-servers.arpa. nstld.iana.org. 2014053714 1800 900 604800 3600

;; Query time: 83 msec
;; SERVER: 8.8.8.8#53(8.8.8.8)
;; WHEN: Mon Mar 02 19:57:16 CST 2015
;; MSG SIZE  rcvd: 119

It seems that the lo doesn't listen on port 53?