I upgraded to ubuntu 12.04 a few days ago, and lost the ability to connect to my works wpa2-enterprise network. I just had the chance to reboot off of a 11.10 live CD to verify that 11.10 works, and thus that it is not some problem with the wireless network.
Looking at wireshark, 12.04 sends a Client Hello which the AP reponds to with "Alert (Level: Fatal, Description: Bad Certificate)" while 11.10 seems to accept the Client Hello message.
I upped wpasupplicant to debug log level on both attempts and am attaching the part of syslog where I was attempting to connect to the access point.
The question
https://answers.launchpad.net/ubuntu/+source/gnome-nettool/+question/183754
looked similar, but their workaround of upgrading the firmware seemed unlikely after I checked that both 11.10 and 12.04 are using the same firmware version.
I'm using a thinkpad with an intel wireless card:
root@myrada:/root# sudo lshw -C network; lsb_release -a; uname -a; sudo rfkill list; dmesg | grep -i firm
*-network
description: Ethernet interface
product: 82579LM Gigabit Network Connection
vendor: Intel Corporation
physical id: 19
bus info: pci@0000:00:19.0
logical name: eth0
version: 04
serial: f0:de:f1:6f:be:a3
size: 1Gbit/s
capacity: 1Gbit/s
width: 32 bits
clock: 33MHz
capabilities: pm msi bus_master cap_list ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd 1000bt-fd autonegotiation
configuration: autonegotiation=on broadcast=yes driver=e1000e driverversion=1.5.1-k duplex=full firmware=0.13-3 ip=131.215.54.184 latency=0 link=yes multicast=yes port=twisted pair speed=1Gbit/s
resources: irq:17 memory:f2500000-f251ffff memory:f252b000-f252bfff ioport:5080(size=32)
*-network
description: Wireless interface
product: Centrino Advanced-N 6205
vendor: Intel Corporation
physical id: 0
bus info: pci@0000:03:00.0
logical name: wlan0
version: 34
serial: a0:88:b4:6a:44:3c
width: 64 bits
clock: 33MHz
capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless
configuration: broadcast=yes driver=iwlwifi driverversion=3.2.0-21-generic firmware=17.168.5.3 build 42301 latency=0 link=no multicast=yes wireless=IEEE 802.11abgn
resources: irq:20 memory:f2400000-f2401fff
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu precise (development branch)
Release: 12.04
Codename: precise
Linux myrada 3.2.0-21-generic #34-Ubuntu SMP Fri Mar 30 04:25:35 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux
0: tpacpi_bluetooth_sw: Bluetooth
Soft blocked: yes
Hard blocked: no
1: phy0: Wireless LAN
Soft blocked: no
Hard blocked: no
[ 0.468570] [Firmware Bug]: ACPI: BIOS _OSI(Linux) query ignored
[ 19.978002] iwlwifi 0000:03:00.0: loaded firmware version 17.168.5.3 build 42301
[ 25.837662] IBM TrackPoint firmware: 0x0e, buttons: 3/3
Actually I think I attached the bug to the wrong component... I suspect the problem is actually with wpasupplicant, but I don't know how to adjust the bug.