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，但如果我尝试运行“ping google.com”或“ping 74.125.39.104”，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。然而，Windows 却运行良好。救救我，别再使用 Windows 了！
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
不要太担心 ping，ping 被服务器基础设施阻止并不罕见。Ping 和 traceroute 通常使用 ICMP。更好的测试是使用wget http://www.google.comHTTP。
首先用来host www.google.com测试 DNS（较旧的 Linux 系统会有nslookup或dig代替host）
$ 主机 www.google.com
www.google.com 是 www.l.google.com 的别名。
www.l.google.com 的地址为 209.85.143.104
www.l.google.com 的地址为 209.85.143.99
$ wget http://www.google.com
--12:21:13-- http://www.google.com/
=> `index.html'
解析 www.google.com...完成。
连接到 www.google.com[209.85.143.99]:80...已连接。
HTTP 请求已发送，正在等待响应...200 OK
长度：未指定 [text/html]
[ ] 9,931 167.21K/秒
12:21:14 (167.21 KB/s) - `index.html' 已保存 [9931]
答案2
你的 /etc/resolve.conf 是什么？它应该指向你的路由器
此文件对于连接互联网非常重要。
答案3
验证 Firestarter 防火墙：
chkconfig -l | grep firestarter
引火装置 0:关闭 1:关闭 2:关闭 3:关闭 4:关闭 5:关闭 6:关闭 S:开启
禁用 Firestarter 防火墙：
sudo chkconfig firestarter off
再检查一下：
chkconfig -l | grep firestarter
引火装置 0:关闭 1:关闭 2:关闭 3:关闭 4:关闭 5:关闭 6:关闭
并停止防火墙：
sudo firestarter-p
继续，尝试再次 ping。