我正在使用 Ubuntu Server14.04.2 LTS和微型无线适配器TP-LINK TL-WN725N。
我在启动时自动连接时遇到了问题。如果我重新启动 10 次，它可能只会连接 4-6 次。当它失败时，我总是可以通过以下方式连接：
sudo ifdown wlan0
sudo ifup wlan0
lsusb输出：
user@ubuntu:~$ lsusb
Bus 001 Device 004: ID 058f:6377 Alcor Micro Corp. Multimedia Card Reader
Bus 001 Device 003: ID 0bda:8179 Realtek Semiconductor Corp.
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 005 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 003 Device 002: ID 046d:c534 Logitech, Inc.
Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
dmesg重新启动网络之前：
user@ubuntu:~$ dmesg
[ 16.105721] EXT4-fs (sda1): re-mounted. Opts: errors=remount-ro
[ 16.801211] R8188EU: INFO indicate disassoc
[ 17.145207] init: failsafe main process (651) killed by TERM signal
[ 17.524498] init: network-manager main process (767) terminated with status 127
[ 17.524520] init: network-manager main process ended, respawning
[ 19.066032] init: plymouth-upstart-bridge main process ended, respawning
interfaces文件：
user@ubuntu:~$ sudo vim /etc/network/interfaces
auto lo
iface lo inet loopback
auto wlan0
iface wlan0 inet static
address 192.168.1.150
netmask 255.255.255.0
gateway 192.168.1.1
wpa-ssid the-ssid
wpa-psk the-pw
dns-nameservers 8.8.8.8 192.168.1.1
ifup连接成功的输出：
user@ubuntu:~$ sudo ifup wlan0
ioctl[SIOCSIWAP]: Operation not permitted
ioctl[SIOCSIWENCODEEXT]: Invalid argument
ioctl[SIOCSIWENCODEEXT]: Invalid argument
更新：其他希望有用的信息：
我跑了wpa_cli -i wlan0 status，它又回来了Failed to connect to non-global ctrl_ifname wlan0 error: Permission denied。
我看了一下/var/log/upstart/network-interface-wlan0.log，它显示了Failed to connect to non-global ctrl_ifname: wlan0 error: Read-only file system。
dmesg后sudo apt-get purge network-manager：
[ 14.539832] R8188EU: Firmware Version 11, SubVersion 1, Signature 0x88e1
[ 14.660066] floppy0: no floppy controllers found
[ 14.660083] work still pending
[ 14.916594] MAC Address = e8:de:27:a3:e7:f6
[ 14.921775] IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready
[ 14.921802] cfg80211: World regulatory domain updated:
[ 14.921806] cfg80211: DFS Master region: unset
[ 14.921809] cfg80211: (start_freq - end_freq @ bandwidth), (max_antenna_gain, max_eirp), (dfs_cac_time)
[ 14.921814] cfg80211: (2402000 KHz - 2472000 KHz @ 40000 KHz), (300 mBi, 2000 mBm), (N/A)
[ 14.921817] cfg80211: (2457000 KHz - 2482000 KHz @ 40000 KHz), (300 mBi, 2000 mBm), (N/A)
[ 14.921821] cfg80211: (2474000 KHz - 2494000 KHz @ 20000 KHz), (300 mBi, 2000 mBm), (N/A)
[ 14.921824] cfg80211: (5170000 KHz - 5250000 KHz @ 40000 KHz), (300 mBi, 2000 mBm), (N/A)
[ 14.921828] cfg80211: (5735000 KHz - 5835000 KHz @ 40000 KHz), (300 mBi, 2000 mBm), (N/A)
[ 16.233140] R8188EU: INFO indicate disassoc
更新 2：结果sudo ifdown wlan0 && sudo ifup -v wlan0：
Configuring interface wlan0=wlan0 (inet)
run-parts --verbose /etc/network/if-pre-up.d
run-parts: executing /etc/network/if-pre-up.d/ethtool
run-parts: executing /etc/network/if-pre-up.d/wireless-tools
run-parts: executing /etc/network/if-pre-up.d/wpasupplicant
wpa_supplicant: wpa-driver nl80211,wext (default)
wpa_supplicant: /sbin/wpa_supplicant -s -B -P /var/run/wpa_supplicant.wlan0.pid -i wlan0 -D nl80211,wext -C /var/run/wpa_supplicant
Starting /sbin/wpa_supplicant...
ioctl[SIOCSIWAP]: Operation not permitted
ioctl[SIOCSIWENCODEEXT]: Invalid argument
ioctl[SIOCSIWENCODEEXT]: Invalid argument
wpa_supplicant: creating sendsigs omission pidfile: /run/sendsigs.omit.d/wpasupplicant.wpa_supplicant.wlan0.pid
wpa_supplicant: ctrl_interface socket located at /var/run/wpa_supplicant/wlan0
wpa_supplicant: configuring network block -- 0
wpa_supplicant: wpa-ssid "the-ssid" -- OK
wpa_supplicant: wpa-psk ***** -- OK
wpa_supplicant: enabling network block 0 -- OK
ip addr add 192.168.1.150/255.255.255.0 broadcast 192.168.1.255 dev wlan0 label wlan0
ip link set dev wlan0 up
ip route add default via 192.168.1.1 dev wlan0
run-parts --verbose /etc/network/if-up.d
run-parts: executing /etc/network/if-up.d/000resolvconf
run-parts: executing /etc/network/if-up.d/ethtool
run-parts: executing /etc/network/if-up.d/ntpdate
run-parts: executing /etc/network/if-up.d/openssh-server
run-parts: executing /etc/network/if-up.d/upstart
run-parts: executing /etc/network/if-up.d/wpasupplicant
答案1
这是相同的 Realtek 驱动程序问题。您可以安装一个修复了问题的良好驱动程序。运行
sudo apt-get install git
git clone https://github.com/lwfinger/rtlwifi_new.git
cd rtlwifi_new
make
sudo make install
然后重新启动。
答案2
使用以下命令：
sudo gedit /var/lib/NetworkManager/NetworkManager.state
确保这些属性相同：
[main]
NetworkingEnabled=true
WirelessEnabled=true
WWANEnabled=true
保存文件并重新启动网络管理器，如下所示：
sudo service networkmanager restart
sudo service network restart
如果您希望使用特定适配器而不是启动整个网络管理器，请使用以下命令
sudo ifconfig
对于无线连接使用
sudo iwconfig
获取计算机上所有适配器的列表及其名称
sudo ifconfig wlan0 up
wlan0如果您有无线连接，您可以将其替换为您机器上的适配器名称。
sudo ifconfig eth0 up
eth0如果您有有线连接，您可以将其替换为您机器上的适配器名称。