我经常无法从笔记本电脑和台式电脑连接 Wi-Fi。这两台机器都运行 Ubuntu 14.04。
有时我就是无法连接到 wifi，唯一的解决方案似乎是重启路由器。重启或重启网络管理器都无济于事。我还遇到了一个建议这样做的解决方案sudo pkill -f wpa_supplicant，我本来以为这可以解决问题，但没有，它又发生了。
问题总是在全新启动或从挂起状态唤醒后发生。一旦我重新启动路由器，问题通常就会解决（尽管有时之后可能还需要重新启动机器），并且连接保持稳定。使用 Windows、Mac OS 或 Android 的其他设备上不会出现此问题。
以下是一次连接尝试的日志/var/log/syslog：
Apr 16 21:30:42 Karl2 NetworkManager[811]: <info> Auto-activating connection 'Bastians WLAN'.
Apr 16 21:30:42 Karl2 NetworkManager[811]: <info> Activation (wlan0) starting connection 'Bastians WLAN'
Apr 16 21:30:42 Karl2 NetworkManager[811]: <info> (wlan0): device state change: disconnected -> prepare (reason 'none') [30 40 0]
Apr 16 21:30:42 Karl2 NetworkManager[811]: <info> NetworkManager state is now CONNECTING
Apr 16 21:30:42 Karl2 NetworkManager[811]: <info> Activation (wlan0) Stage 1 of 5 (Device Prepare) scheduled...
Apr 16 21:30:42 Karl2 NetworkManager[811]: <info> Activation (wlan0) Stage 1 of 5 (Device Prepare) started...
Apr 16 21:30:42 Karl2 NetworkManager[811]: <info> Activation (wlan0) Stage 2 of 5 (Device Configure) scheduled...
Apr 16 21:30:42 Karl2 NetworkManager[811]: <info> Activation (wlan0) Stage 1 of 5 (Device Prepare) complete.
Apr 16 21:30:42 Karl2 NetworkManager[811]: <info> Activation (wlan0) Stage 2 of 5 (Device Configure) starting...
Apr 16 21:30:42 Karl2 NetworkManager[811]: <info> (wlan0): device state change: prepare -> config (reason 'none') [40 50 0]
Apr 16 21:30:42 Karl2 NetworkManager[811]: <info> Activation (wlan0/wireless): access point 'Bastians WLAN' has security, but secrets are required.
Apr 16 21:30:42 Karl2 NetworkManager[811]: <info> (wlan0): device state change: config -> need-auth (reason 'none') [50 60 0]
Apr 16 21:30:42 Karl2 NetworkManager[811]: <info> Activation (wlan0) Stage 2 of 5 (Device Configure) complete.
Apr 16 21:30:42 Karl2 NetworkManager[811]: <info> Activation (wlan0) Stage 1 of 5 (Device Prepare) scheduled...
Apr 16 21:30:42 Karl2 NetworkManager[811]: <info> Activation (wlan0) Stage 1 of 5 (Device Prepare) started...
Apr 16 21:30:42 Karl2 NetworkManager[811]: <info> (wlan0): device state change: need-auth -> prepare (reason 'none') [60 40 0]
Apr 16 21:30:42 Karl2 NetworkManager[811]: <info> Activation (wlan0) Stage 2 of 5 (Device Configure) scheduled...
Apr 16 21:30:42 Karl2 NetworkManager[811]: <info> Activation (wlan0) Stage 1 of 5 (Device Prepare) complete.
Apr 16 21:30:42 Karl2 NetworkManager[811]: <info> Activation (wlan0) Stage 2 of 5 (Device Configure) starting...
Apr 16 21:30:42 Karl2 NetworkManager[811]: <info> (wlan0): device state change: prepare -> config (reason 'none') [40 50 0]
Apr 16 21:30:42 Karl2 NetworkManager[811]: <info> Activation (wlan0/wireless): connection 'Bastians WLAN' has security, and secrets exist. No new secrets needed.
Apr 16 21:30:42 Karl2 NetworkManager[811]: <info> Config: added 'ssid' value 'Bastians WLAN'
Apr 16 21:30:42 Karl2 NetworkManager[811]: <info> Config: added 'scan_ssid' value '1'
Apr 16 21:30:42 Karl2 NetworkManager[811]: <info> Config: added 'key_mgmt' value 'WPA-PSK'
Apr 16 21:30:42 Karl2 NetworkManager[811]: <info> Config: added 'auth_alg' value 'OPEN'
Apr 16 21:30:42 Karl2 NetworkManager[811]: <info> Config: added 'psk' value '<omitted>'
Apr 16 21:30:42 Karl2 NetworkManager[811]: <info> Activation (wlan0) Stage 2 of 5 (Device Configure) complete.
Apr 16 21:30:42 Karl2 NetworkManager[811]: <info> Config: set interface ap_scan to 1
Apr 16 21:30:42 Karl2 NetworkManager[811]: <info> (wlan0): supplicant interface state: disconnected -> scanning
Apr 16 21:31:07 Karl2 NetworkManager[811]: <warn> Activation (wlan0/wireless): association took too long, failing activation.
Apr 16 21:31:07 Karl2 NetworkManager[811]: <info> (wlan0): device state change: config -> failed (reason 'SSID not found') [50 120 53]
Apr 16 21:31:07 Karl2 NetworkManager[811]: <info> NetworkManager state is now DISCONNECTED
Apr 16 21:31:07 Karl2 NetworkManager[811]: <info> Marking connection 'Bastians WLAN' invalid.
Apr 16 21:31:07 Karl2 NetworkManager[811]: <warn> Activation (wlan0) failed for connection 'Bastians WLAN'
Apr 16 21:31:07 Karl2 NetworkManager[811]: <info> (wlan0): device state change: failed -> disconnected (reason 'none') [120 30 0]
Apr 16 21:31:07 Karl2 NetworkManager[811]: <info> (wlan0): deactivating device (reason 'none') [0]
Apr 16 21:31:07 Karl2 NetworkManager[811]: <info> (wlan0): supplicant interface state: scanning -> disconnected
Apr 16 21:31:07 Karl2 NetworkManager[811]: <warn> Couldn't disconnect supplicant interface: This interface is not connected.
答案1
我之前遇到过类似的问题，我建议安装 wicd 网络管理器，安装说明可以找到这里