有人在我们网络中的一台机器上安装并配置了 ubuntu。我最近注意到所有 DNS 查找都失败了，但我找不到解决方案。我尝试了多个名称服务器，根据谷歌的建议编辑了数百次接口文件，但都不起作用。
以下是一些信息，如果有人有任何想法，我将不胜感激。谢谢
nslookup
administrator@redmine:~$ nslookup google.com
;; connection timed out; no servers could be reached
administrator@redmine:~$ nslookup localhost
;; connection timed out; no servers could be reached
nslookup 的 tcpdump [需要 3 次查找才能获得任何 tcpdump 输出] - 已编辑
administrator@redmine:~$ sudo tcpdump -vvv -i any port 53
tcpdump: listening on any, link-type LINUX_SLL (Linux cooked), capture size 96 bytes
10:26:51.965297 IP (tos 0x0, ttl 64, id 9167, offset 0, flags [none], proto UDP (17), length 56)
10.80.15.5.56365 > 208.67.222.222.domain: [bad udp cksum 988f!] 61133+ A? google.com. (28)
10:26:51.965595 IP (tos 0x0, ttl 64, id 25587, offset 0, flags [DF], proto UDP (17), length 73)
10.80.15.5.57551 > 208.67.222.222.domain: [bad udp cksum ff0c!] 9477+ PTR? 222.222.67.208.in-addr.arpa. (45)
10:26:52.965437 IP (tos 0x0, ttl 64, id 37960, offset 0, flags [none], proto UDP (17), length 56)
10.80.15.5.45006 > 208.67.220.220.domain: [bad udp cksum fbbf!] 61133+ A? google.com. (28)
10:26:56.967724 IP (tos 0x0, ttl 64, id 26087, offset 0, flags [DF], proto UDP (17), length 73)
10.80.15.5.38794 > 208.67.220.220.domain: [bad udp cksum 485a!] 9477+ PTR? 222.222.67.208.in-addr.arpa. (45)
10:26:57.965482 IP (tos 0x0, ttl 64, id 9168, offset 0, flags [none], proto UDP (17), length 56)
10.80.15.5.56365 > 208.67.222.222.domain: [bad udp cksum 988f!] 61133+ A? google.com. (28)
10:26:58.965605 IP (tos 0x0, ttl 64, id 37961, offset 0, flags [none], proto UDP (17), length 56)
10.80.15.5.45006 > 208.67.220.220.domain: [bad udp cksum fbbf!] 61133+ A? google.com. (28)
10:27:01.972798 IP (tos 0x0, ttl 64, id 25588, offset 0, flags [DF], proto UDP (17), length 73)
10.80.15.5.57551 > 208.67.222.222.domain: [bad udp cksum ff0c!] 9477+ PTR? 222.222.67.208.in-addr.arpa. (45)
10:27:03.965726 IP (tos 0x0, ttl 64, id 9169, offset 0, flags [none], proto UDP (17), length 56)
10.80.15.5.56365 > 208.67.222.222.domain: [bad udp cksum 988f!] 61133+ A? google.com. (28)
10:27:04.965844 IP (tos 0x0, ttl 64, id 37962, offset 0, flags [none], proto UDP (17), length 56)
10.80.15.5.45006 > 208.67.220.220.domain: [bad udp cksum fbbf!] 61133+ A? google.com. (28)
10:27:06.974911 IP (tos 0x0, ttl 64, id 26088, offset 0, flags [DF], proto UDP (17), length 73)
10.80.15.5.38794 > 208.67.220.220.domain: [bad udp cksum 485a!] 9477+ PTR? 222.222.67.208.in-addr.arpa. (45)
10:27:11.255383 IP (tos 0x0, ttl 64, id 9170, offset 0, flags [none], proto UDP (17), length 56)
10.80.15.5.46416 > 208.67.222.222.domain: [bad udp cksum 1dab!] 64037+ A? google.com. (28)
10:27:11.980136 IP (tos 0x0, ttl 64, id 27588, offset 0, flags [DF], proto UDP (17), length 69)
10.80.15.5.41940 > 208.67.222.222.domain: [bad udp cksum 12f8!] 57952+ PTR? 5.15.80.10.in-addr.arpa. (41)
10:27:12.255497 IP (tos 0x0, ttl 64, id 37963, offset 0, flags [none], proto UDP (17), length 56)
10.80.15.5.34434 > 208.67.220.220.domain: [bad udp cksum efdd!] 64037+ A? google.com. (28)
10:27:16.983093 IP (tos 0x0, ttl 64, id 28089, offset 0, flags [DF], proto UDP (17), length 69)
10.80.15.5.33410 > 208.67.220.220.domain: [bad udp cksum 691d!] 57952+ PTR? 5.15.80.10.in-addr.arpa. (41)
10:27:17.255564 IP (tos 0x0, ttl 64, id 9171, offset 0, flags [none], proto UDP (17), length 56)
10.80.15.5.46416 > 208.67.222.222.domain: [bad udp cksum 1dab!] 64037+ A? google.com. (28)
10:27:18.255675 IP (tos 0x0, ttl 64, id 37964, offset 0, flags [none], proto UDP (17), length 56)
10.80.15.5.34434 > 208.67.220.220.domain: [bad udp cksum efdd!] 64037+ A? google.com. (28)
10:27:21.988171 IP (tos 0x0, ttl 64, id 27589, offset 0, flags [DF], proto UDP (17), length 69)
10.80.15.5.41940 > 208.67.222.222.domain: [bad udp cksum 12f8!] 57952+ PTR? 5.15.80.10.in-addr.arpa. (41)
10:27:23.255805 IP (tos 0x0, ttl 64, id 9172, offset 0, flags [none], proto UDP (17), length 56)
10.80.15.5.46416 > 208.67.222.222.domain: [bad udp cksum 1dab!] 64037+ A? google.com. (28)
10:27:24.255925 IP (tos 0x0, ttl 64, id 37965, offset 0, flags [none], proto UDP (17), length 56)
10.80.15.5.34434 > 208.67.220.220.domain: [bad udp cksum efdd!] 64037+ A? google.com. (28)
10:27:26.991768 IP (tos 0x0, ttl 64, id 28090, offset 0, flags [DF], proto UDP (17), length 69)
10.80.15.5.33410 > 208.67.220.220.domain: [bad udp cksum 691d!] 57952+ PTR? 5.15.80.10.in-addr.arpa. (41)
10:27:31.165191 IP (tos 0x0, ttl 64, id 9173, offset 0, flags [none], proto UDP (17), length 56)
10.80.15.5.47147 > 208.67.222.222.domain: [bad udp cksum 55b3!] 61202+ A? google.com. (28)
10:27:31.997034 IP (tos 0x0, ttl 64, id 29590, offset 0, flags [DF], proto UDP (17), length 73)
10.80.15.5.37414 > 208.67.222.222.domain: [bad udp cksum 3353!] 11646+ PTR? 220.220.67.208.in-addr.arpa. (45)
10:27:32.165303 IP (tos 0x0, ttl 64, id 37966, offset 0, flags [none], proto UDP (17), length 56)
10.80.15.5.57432 > 208.67.220.220.domain: [bad udp cksum 2c8f!] 61202+ A? google.com. (28)
10:27:36.999487 IP (tos 0x0, ttl 64, id 30090, offset 0, flags [DF], proto UDP (17), length 73)
10.80.15.5.34374 > 208.67.220.220.domain: [bad udp cksum 1763!] 11646+ PTR? 220.220.67.208.in-addr.arpa. (45)
10:27:37.165381 IP (tos 0x0, ttl 64, id 9174, offset 0, flags [none], proto UDP (17), length 56)
10.80.15.5.47147 > 208.67.222.222.domain: [bad udp cksum 55b3!] 61202+ A? google.com. (28)
10:27:38.165507 IP (tos 0x0, ttl 64, id 37967, offset 0, flags [none], proto UDP (17), length 56)
10.80.15.5.57432 > 208.67.220.220.domain: [bad udp cksum 2c8f!] 61202+ A? google.com. (28)
10:27:42.004572 IP (tos 0x0, ttl 64, id 29591, offset 0, flags [DF], proto UDP (17), length 73)
10.80.15.5.37414 > 208.67.222.222.domain: [bad udp cksum 3353!] 11646+ PTR? 220.220.67.208.in-addr.arpa. (45)
10:27:43.165623 IP (tos 0x0, ttl 64, id 9175, offset 0, flags [none], proto UDP (17), length 56)
10.80.15.5.47147 > 208.67.222.222.domain: [bad udp cksum 55b3!] 61202+ A? google.com. (28)
10:27:44.165729 IP (tos 0x0, ttl 64, id 37968, offset 0, flags [none], proto UDP (17), length 56)
10.80.15.5.57432 > 208.67.220.220.domain: [bad udp cksum 2c8f!] 61202+ A? google.com. (28)
10:27:47.009170 IP (tos 0x0, ttl 64, id 30091, offset 0, flags [DF], proto UDP (17), length 73)
10.80.15.5.34374 > 208.67.220.220.domain: [bad udp cksum 1763!] 11646+ PTR? 220.220.67.208.in-addr.arpa. (45)
/etc/hosts
administrator@redmine:~$ cat /etc/hosts
127.0.0.1 localhost localhost.localdomain redmine redmine.hiddendomain.com
/etc/resolv.conf
administrator@redmine:~$ cat /etc/resolv.conf
### OPENDNS ###
nameserver 208.67.222.222
nameserver 208.67.220.220
### GOOGLE NS ###
#nameserver 8.8.8.8
#nameserver 8.8.4.4
/etc/网络/接口
administrator@redmine:~$ cat /etc/network/interfaces
# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).
# The loopback network interface
auto lo
iface lo inet loopback
#The primary network
auto eth0
iface eth0 inet static
address 10.80.15.5
netmask 255.255.255.0
network 10.80.15.0
broadcast 10.80.15.255
gateway 10.80.15.254
## Try this just in case resolv.conf isn't being read properly
dns-nameserver 8.8.8.8
/etc/nsswitch.conf
cat /etc/nsswitch.conf
# /etc/nsswitch.conf
#
# Example configuration of GNU Name Service Switch functionality.
# If you have the `glibc-doc-reference' and `info' packages installed, try:
# `info libc "Name Service Switch"' for information about this file.
passwd: compat
group: compat
shadow: compat
hosts: files dns
networks: files
protocols: db files
services: db files
ethers: db files
rpc: db files
netgroup: nis
/etc/主机.conf
multi on
但是我可以 telnet，所以它不是防火墙（但你已经从 tcpdump 中知道了这一点）
administrator@redmine:~$ telnet 8.8.8.8 53
Trying 8.8.8.8...
Connected to 8.8.8.8.
Escape character is '^]'.
Connection closed by foreign host.
更新：感谢 ladadada* 发现我的愚蠢错误。但是现在我又回到了原来的问题。它使用正确的 DNS 服务器（您可以从 tcpdump 中看到），但是 nslookup/dig 仍然说无法访问任何服务器。我已经测试过，我可以通过端口 53 远程登录到两个 opendns 服务器。奇怪的是，我必须运行 nslookup 3 次才能从 tcpdump 获得任何输出，前 2 次查找没有通过 tcpdump 输出任何内容（不确定这是否相关）。
再次，我们将非常感谢任何帮助、建议等。
答案1
你/etc/resolv.conf看起来应该是这样的：
### OPENDNS ###
nameserver 208.67.222.222
nameserver 208.67.220.220
### GOOGLE NS ###
#nameserver 8.8.8.8
#nameserver 8.8.4.4
如果没有nameserver关键字，IP 地址本身就没有任何意义。