Linux无线ESSID:off/any的错误
我用的Distribution是SUSE，昨天上网发现无线网络突然扫描不了，在命令行下输入iwconfig wlan0
得到的结果为：
wlan0     IEEE 802.11bgn  ESSID:off/any  
          Mode:Managed  Access Point: Not-Associated   Tx-Power=0 dBm   
          Retry  long limit:7   RTS thr:off   Fragment thr:off
          Encryption key:off
          Power Management:off
这个信息说明任何无线都无法被扫描到。

查了很多资料都不知道是什么原因。
输入命令/etc/init.d/network restart
得到的结果为：
Shutting down network interfaces:
    eth0      device: Realtek Semiconductor Co., Ltd. RTL8111/8168B
              No configuration found for eth0
              Nevertheless the interface will be shut down.          done
    wlan0     device: Atheros Communications Inc. AR9485 Wireless N  done
Shutting down service network  .  .  .  .  .  .  .  .  .             done
Hint: you may set mandatory devices in /etc/sysconfig/network/config
Setting up network interfaces:
    eth0      device: Realtek Semiconductor Co., Ltd. RTL8111/8168B
              No configuration found for eth0                        unused
    wlan0     device: Atheros Communications Inc. AR9485 Wireless N
    wlan0     warning: using NO encryption
    wlan0     Starting DHCP4+DHCP6 client. . . . . . . .  
    wlan0     DHCP4 continues in background
    wlan0     DHCP6 continues in background                          waiting
Setting up service network  .  .  .  .  .  .  .  .  .  .             done
SuSEfirewall2: Setting up rules from /etc/sysconfig/SuSEfirewall2 ...
SuSEfirewall2: using default zone 'ext' for interface eth0
SuSEfirewall2: batch committing...
SuSEfirewall2: Firewall rules successfully set

注意，上面的信息中有一个异常：wlan0     DHCP6 continues in background                          waiting
进到图形界面的“网络设置”中的“全局选项”，如下图所示：

发现图中的“启用IPv6”选项被勾起来了。把该选项前面的勾去掉，无线网络恢复可以为正常扫描。

问题解决！