我有一台使用以太网连接互联网的 PC。使用 Ubuntu，我能够使用 nslookup 解析域名，但如果我尝试打开互联网页面或使用 wget，它不起作用。
我曾在两台上网本上使用过 Arch Linux、Mint 和 Ubuntu Live，但均未成功。不过，Windows 运行良好。
ifconfig：
sudo ifconfig eth0
eth0 Link encap:Ethernet HWaddr 00:26:18:80:79:18
inet addr:10.20.6.180 Bcast:10.20.7.255 Mask:255.255.254.0
inet6 addr: fe80::226:18ff:fe80:7918/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:5751 errors:0 dropped:0 overruns:0 frame:0
TX packets:2397 errors:0 dropped:0 overruns:0 carrier:17
collisions:0 txqueuelen:1000
RX bytes:659976 (659.9 KB) TX bytes:253881 (253.8 KB)
Interrupt:40
路线：
route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
10.20.6.0 0.0.0.0 255.255.254.0 U 1 0 0 eth0
169.254.0.0 0.0.0.0 255.255.0.0 U 1000 0 0 eth0
0.0.0.0 10.20.6.1 0.0.0.0 UG 0 0 0 eth0
0.0.0.0 10.20.6.1 0.0.0.0 UG 202 0 0 eth0
网络状态：
netstat -nr
Kernel IP routing table
Destination Gateway Genmask Flags MSS Window irtt Iface
10.20.6.0 0.0.0.0 255.255.254.0 U 0 0 0 eth0
169.254.0.0 0.0.0.0 255.255.0.0 U 0 0 0 eth0
0.0.0.0 10.20.6.1 0.0.0.0 UG 0 0 0 eth0
0.0.0.0 10.20.6.1 0.0.0.0 UG 0 0 0 eth0
iptables：
sudo iptables -L
Chain INPUT (policy ACCEPT)
target prot opt source destination
Chain FORWARD (policy ACCEPT)
target prot opt source destination
Chain OUTPUT (policy ACCEPT)
target prot opt source destination
解析.conf：
cat /etc/resolv.conf
# Generated by resolvconf
search uni-mannheim.de
nameserver 134.155.96.51
nameserver 134.155.96.53
tracepath 不起作用：
sudo tracepath www.google.com
1: laptop.local 0.342ms pmtu 1500
1: no reply
2: no reply
3: no reply
4: no reply
/etc/主机.conf
sudo cat /etc/host.conf
# The "order" line is only used by old versions of the C library.
order hosts,bind
multi on
/etc/nsswitch.conf
sudo 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 mdns4_minimal [NOTFOUND=return] dns mdns4
networks: files
protocols: db files
services: db files
ethers: db files
rpc: db files
netgroup: nis
nslookup google.com
nslookup google.com
Server: 134.155.96.51
Address: 134.155.96.51#53
Non-authoritative answer:
Name: google.com
Address: 74.125.39.104
Name: google.com
Address: 74.125.39.105
Name: google.com
Address: 74.125.39.106
Name: google.com
Address: 74.125.39.147
Name: google.com
Address: 74.125.39.99
Name: google.com
Address: 74.125.39.103
wget google.com
wget google.com
--2011-08-17 11:05:01-- http://google.com/
Resolving google.com... 74.125.39.99, 74.125.39.103, 74.125.39.104, ...
Connecting to google.com|74.125.39.99|:80...
挖掘 google.com
tracepath 不起作用，但 dig 起作用
dig google.com
; <<>> DiG 9.7.3 <<>> google.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 2643
;; flags: qr rd ra; QUERY: 1, ANSWER: 6, AUTHORITY: 4, ADDITIONAL: 4
;; QUESTION SECTION:
;google.com. IN A
;; ANSWER SECTION:
google.com. 175 IN A 74.125.39.103
google.com. 175 IN A 74.125.39.104
google.com. 175 IN A 74.125.39.105
google.com. 175 IN A 74.125.39.106
google.com. 175 IN A 74.125.39.147
google.com. 175 IN A 74.125.39.99
;; AUTHORITY SECTION:
google.com. 104161 IN NS ns4.google.com.
google.com. 104161 IN NS ns3.google.com.
google.com. 104161 IN NS ns1.google.com.
google.com. 104161 IN NS ns2.google.com.
;; ADDITIONAL SECTION:
ns1.google.com. 277325 IN A 216.239.32.10
ns2.google.com. 277325 IN A 216.239.34.10
ns3.google.com. 277325 IN A 216.239.36.10
ns4.google.com. 277325 IN A 216.239.38.10
;; Query time: 2 msec
;; SERVER: 134.155.96.51#53(134.155.96.51)
;; WHEN: Wed Aug 17 11:06:14 2011
;; MSG SIZE rcvd: 260
答案1
我的德语确实生疏了（已经20年了...），但基于此信息如果你确实在使用 uni-mannheim.de 网络，你需要指示你的软件使用他们的代理（或直接使用他们的 vpn）。要验证，请尝试
echo "http_proxy = http://www-cache.uni-mannheim.de:3128/" | sudo tee -a /etc/wgetrc
echo "use_proxy = on" | sudo tee -a /etc/wgetrc
wget http://www.google.com/
如果此方法有效，您或许应该改用提供的 vpn 连接（它可能支持更多协议）。或者，您必须指示所有相关软件使用此代理。
/etc/wgetrc测试完成后，不要忘记删除这两行。