我正在使用无线连接。
屏幕右上角的连接图标表明我确实已连接，但更新管理器、电子邮件连接和互联网访问失败。
操作系统是 Ubuntu 12.04 LTS。我使用工作电脑访问此帮助网站，希望得到一些有关这些问题的指导。我对 Ubuntu 和 Linux 都很陌生。上次更新日期为 7 月 30 日。
话虽如此，任何有关诊断步骤的建议或任何其他有用的指导都会受到欢迎。
ping -c4 4.2.2.2并route | grep default没有返回任何东西。
ifconfig：
eth0 Link encap:Ethernet HWaddr 00:22:4d:50:b3:9e
UP BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)
Interrupt:20 Memory:f0400000-f0420000
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:3384 errors:0 dropped:0 overruns:0 frame:0
TX packets:3384 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:187028 (187.0 KB) TX bytes:187028 (187.0 KB)
wlan0 Link encap:Ethernet HWaddr 6c:62:6d:23:d0:c0
inet addr:192.168.0.5 Bcast:192.168.0.255 Mask:255.255.255.0
inet6 addr: fe80::6e62:6dff:fe23:d0c0/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:32293 errors:0 dropped:0 overruns:0 frame:0
TX packets:145 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:2382888 (2.3 MB) TX bytes:10990 (10.9 KB)
IP地址：
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast state DOWN qlen 1000
link/ether 00:22:4d:50:b3:9e brd ff:ff:ff:ff:ff:ff
3: wlan0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP qlen 1000
link/ether 6c:62:6d:23:d0:c0 brd ff:ff:ff:ff:ff:ff
inet 192.168.0.5/24 brd 192.168.0.255 scope global wlan0
inet6 fe80::6e62:6dff:fe23:d0c0/64 scope link
valid_lft forever preferred_lft forever
配置：
eth0 no wireless extensions.
lo no wireless extensions.
wlan0 IEEE 802.11bgn ESSID:"CGnetwork"
Mode:Managed Frequency:2.437 GHz Access Point: A0:21:B7:F7:EF:DB
Bit Rate=72.2 Mb/s Tx-Power=20 dBm
Retry long limit:7 RTS thr:off Fragment thr:off
Power Management:on
Link Quality=59/70 Signal level=-51 dBm
Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:13 Invalid misc:6 Missed beacon:0
ping 和 dconf read 没有产生任何结果。
iptables -L：
Chain INPUT (policy DROP)
target prot opt source destination
ufw-before-logging-input all -- anywhere anywhere
ufw-before-input all -- anywhere anywhere
ufw-after-input all -- anywhere anywhere
ufw-after-logging-input all -- anywhere anywhere
ufw-reject-input all -- anywhere anywhere
ufw-track-input all -- anywhere anywhere
Chain FORWARD (policy DROP)
target prot opt source destination
ufw-before-logging-forward all -- anywhere anywhere
ufw-before-forward all -- anywhere anywhere
ufw-after-forward all -- anywhere anywhere
ufw-after-logging-forward all -- anywhere anywhere
ufw-reject-forward all -- anywhere anywhere
Chain OUTPUT (policy DROP)
target prot opt source destination
ufw-before-logging-output all -- anywhere anywhere
ufw-before-output all -- anywhere anywhere
ufw-after-output all -- anywhere anywhere
ufw-after-logging-output all -- anywhere anywhere
ufw-reject-output all -- anywhere anywhere
ufw-track-output all -- anywhere anywhere
Chain ufw-after-forward (1 references)
target prot opt source destination
Chain ufw-after-input (1 references)
target prot opt source destination
ufw-skip-to-policy-input udp -- anywhere anywhere udp dpt:netbios-ns
ufw-skip-to-policy-input udp -- anywhere anywhere udp dpt:netbios-dgm
ufw-skip-to-policy-input tcp -- anywhere anywhere tcp dpt:netbios-ssn
ufw-skip-to-policy-input tcp -- anywhere anywhere tcp dpt:microsoft-ds
ufw-skip-to-policy-input udp -- anywhere anywhere udp dpt:bootps
ufw-skip-to-policy-input udp -- anywhere anywhere udp dpt:bootpc
ufw-skip-to-policy-input all -- anywhere anywhere ADDRTYPE match dst-type BROADCAST
Chain ufw-after-logging-forward (1 references)
target prot opt source destination
LOG all -- anywhere anywhere limit: avg 3/min burst 10 LOG level warning prefix "[UFW BLOCK] "
Chain ufw-after-logging-input (1 references)
target prot opt source destination
LOG all -- anywhere anywhere limit: avg 3/min burst 10 LOG level warning prefix "[UFW BLOCK] "
Chain ufw-after-logging-output (1 references)
target prot opt source destination
LOG all -- anywhere anywhere limit: avg 3/min burst 10 LOG level warning prefix "[UFW BLOCK] "
Chain ufw-after-output (1 references)
target prot opt source destination
Chain ufw-before-forward (1 references)
target prot opt source destination
ufw-user-forward all -- anywhere anywhere
Chain ufw-before-input (1 references)
target prot opt source destination
ACCEPT all -- anywhere anywhere
ACCEPT all -- anywhere anywhere state RELATED,ESTABLISHED
ufw-logging-deny all -- anywhere anywhere state INVALID
DROP all -- anywhere anywhere state INVALID
ACCEPT icmp -- anywhere anywhere icmp destination-unreachable
ACCEPT icmp -- anywhere anywhere icmp source-quench
ACCEPT icmp -- anywhere anywhere icmp time-exceeded
ACCEPT icmp -- anywhere anywhere icmp parameter-problem
ACCEPT icmp -- anywhere anywhere icmp echo-request
ACCEPT udp -- anywhere anywhere udp spt:bootps dpt:bootpc
ufw-not-local all -- anywhere anywhere
ACCEPT udp -- anywhere 224.0.0.251 udp dpt:mdns
ACCEPT udp -- anywhere 239.255.255.250 udp dpt:1900
ufw-user-input all -- anywhere anywhere
Chain ufw-before-logging-forward (1 references)
target prot opt source destination
Chain ufw-before-logging-input (1 references)
target prot opt source destination
Chain ufw-before-logging-output (1 references)
target prot opt source destination
Chain ufw-before-output (1 references)
target prot opt source destination
ACCEPT all -- anywhere anywhere
ACCEPT all -- anywhere anywhere state RELATED,ESTABLISHED
ufw-user-output all -- anywhere anywhere
Chain ufw-logging-allow (0 references)
target prot opt source destination
LOG all -- anywhere anywhere limit: avg 3/min burst 10 LOG level warning prefix "[UFW ALLOW] "
Chain ufw-logging-deny (2 references)
target prot opt source destination
RETURN all -- anywhere anywhere state INVALID limit: avg 3/min burst 10
LOG all -- anywhere anywhere limit: avg 3/min burst 10 LOG level warning prefix "[UFW BLOCK] "
Chain ufw-not-local (1 references)
target prot opt source destination
RETURN all -- anywhere anywhere ADDRTYPE match dst-type LOCAL
RETURN all -- anywhere anywhere ADDRTYPE match dst-type MULTICAST
RETURN all -- anywhere anywhere ADDRTYPE match dst-type BROADCAST
ufw-logging-deny all -- anywhere anywhere limit: avg 3/min burst 10
DROP all -- anywhere anywhere
Chain ufw-reject-forward (1 references)
target prot opt source destination
Chain ufw-reject-input (1 references)
target prot opt source destination
Chain ufw-reject-output (1 references)
target prot opt source destination
Chain ufw-skip-to-policy-forward (0 references)
target prot opt source destination
DROP all -- anywhere anywhere
Chain ufw-skip-to-policy-input (7 references)
target prot opt source destination
DROP all -- anywhere anywhere
Chain ufw-skip-to-policy-output (0 references)
target prot opt source destination
DROP all -- anywhere anywhere
Chain ufw-track-input (1 references)
target prot opt source destination
Chain ufw-track-output (1 references)
target prot opt source destination
Chain ufw-user-forward (1 references)
target prot opt source destination
Chain ufw-user-input (1 references)
target prot opt source destination
Chain ufw-user-limit (0 references)
target prot opt source destination
LOG all -- anywhere anywhere limit: avg 3/min burst 5 LOG level warning prefix "[UFW LIMIT BLOCK] "
REJECT all -- anywhere anywhere reject-with icmp-port-unreachable
Chain ufw-user-limit-accept (0 references)
target prot opt source destination
ACCEPT all -- anywhere anywhere
Chain ufw-user-logging-forward (0 references)
target prot opt source destination
Chain ufw-user-logging-input (0 references)
target prot opt source destination
Chain ufw-user-logging-output (0 references)
target prot opt source destination
Chain ufw-user-output (1 references)
target prot opt source destination
nm 工具：
NetworkManager 工具
状态：断开连接
- 设备：wlan0 ----------------------------------------------------------------
类型：802.11 WiFi
驱动程序：rt2800usb
状态：断开连接
默认值： no
硬件地址：6C：62：6D：23：D0：C0
功能：
无线属性
WEP 加密：是
WPA 加密：是
WPA2 加密：是
无线接入点
- 设备：eth0 -----------------------------------------------------------------
类型：有线
驱动程序：e1000e
状态：不可用
默认值： no
硬件地址：00：22：4D：50：B3：9E
功能：
载波检测：是
连线属性
承运商： 关闭
答案1
首先，检查网络管理器是否没有管理您的连接，单击用户名旁边的网络小程序，并确保“启用网络”、“有线”和“无线”都处于活动状态。
此外，似乎没有设置网关，这可能是因为您的 DHCP 配置未被捕获，或者您已手动设置网络配置。如果您设置了网络配置手动的，您应该验证网关是否已填写（您不必使用与我的屏幕截图相同的值，只需查看在使用手动方法时应填写哪些值即可)：
如果你的方法是自动的，然后尝试禁用你的 UFW。
你的 UFW 规则丢弃了大部分软件包，请考虑允许所有输出包，或者至少是需要目标端口的包，从您的问题来看，您需要允许输出到端口 TCP:80 (http) 和输入/输出 UDP:53 (DHCP)。您可以在这篇维基百科文章。如果您不确定，只需完全停用 UFW 规则，检查您是否有互联网。
您可以检查哪些包被删除了dmesg | grep UFW（这可能是一个很长的列表）。