Wireless adapter on Lenovo Z580 does not connect to Internet in Linux although it detects all the wireless networks. Finally, got the settings right to enable the use of built-in Broadcom 4313 Network controller : Broadcom Corporation BCM4313 802.11bgn Wireless Network Adapter [14e4:4727] (rev 01)
Here are the steps.
Open a terminal window. In the /etc/modprobe.d/blacklist.conf blacklist ssb, b43, brcmsmac, bcma with
$ sudo gedit /etc/modprobe.d/blacklist.conf <enter>
Add the following lines:
Download and install the bcmwl-kernel-source package as:
$ sudo apt-get install bcmwl-kernel-source <enter>
After above steps, the laptop did connect to the wireless router and showed full signal strength, but trying to surf the internet or ping any addresses, it never connected. Looking at this post, http://askubuntu.com/questions/391979/wireless-connected-but-no-internet-bcm4313, turn off Wireless N network on the wireless router and it works very well.
In short, even though the laptop (Lenovo Z580) has a wireless card that support 802.11a/b/g/n, you can only use b & g and not n. Hope we get a fix to this bug in the next upgrade. Till then, it works as it is.