After upgrade to 15.10 Wifi to a corporate network (WPA2) is not working anymore

Solution 1:

I got the same issue here: The problem is the wpa_supplicant 2.4 as you can read here: http://community.arubanetworks.com/t5/Unified-Wired-Wireless-Access/Internal-radius-server-incompatibility-with-the-new-wpa/td-p/236602

If you do a downgrade to 2.3 this problem will be resolve !

Solution 2:

The problem is that some routers and/or access points uses WPA2 Enterprise with weak DH key and Network Manager 2.4 doesn't connect to those networks.

Normally this issue happening on Ubuntu >= 15.10. At the moment, a temporary workaround is to downgrade wpa_supplicant to 2.1 (from Ubuntu 15.04) with the following instructions:

echo "deb http://london.mirrors.linode.com/ubuntu/ vivid main" | sudo tee /etc/apt/sources.list.d/vivid.list
echo -e "Package: *\nPin: release o=Ubuntu,n=vivid\nPin-Priority: -1" | sudo tee cat /etc/apt/preferences.d/vivid
sudo apt-get update
sudo apt-get install wpasupplicant=2.1-0ubuntu7
sudo apt-mark hold wpasupplicant
sudo /etc/init.d/network-manager restart

References:

• https://weakdh.org/
• http://viranzo.blogs.upv.es/2016/02/12/downgrade-wpa_supplicant-ubuntu-15-10-2/