How do I get my Lenovo T61 to connect to a wireless network?

Question

I have a Lenovo Thinkpad T61 and the wireless works just fine so I installed Ubuntu straight away only to find that the wireless will not connect, it will see the networks but just not connect. Has anyone managed to solve this all the forums seem to relate to Ubuntu 9.04 and before.

Edit:Sorry about that, I didn't realise that there were 2 models mine is the Intel Corporation PRO/Wireless 4965 AG or AGN [Kedron] Network Connection. Any help is much appreciated.

Solution

If the machine is running 11.04 or 11.10 you need to disable "n" by running this in a terminal:

gksu gedit /etc/modprobe.d/options.conf

and adding this line to the file:

options iwl4965 11n_disable=1

Reboot and try to connect again.

Ubuntu 12.04LTS solves this problem (I will update if this changes).

Edit: So far versions after and including Ubuntu 12.04LTS do not have this issue with the Intel 4965 wireless card.

Comments

[titaniumtux]

I looked that laptop up, looks like they can ship with two different WLAN cards...Intel 3945ABG 802.11abg or Intel 4965AGN 802.11abgn. Please run lspci in the terminal and edit your question to include which wireless adapter you have in there.

[Ross Fleming]

I have managed to get it to connect to my router now by disabling the "n" mode and it works fine....except I've noticed that after downloading for around 1-2 mins it stops. It doesn't disconnect or anything just stops. I have tested and I can upload files to my server that are huge and take hours but cannot download them either so it's not just a slow connection. Any ideas?

[Ross Fleming]

The "n" disabling sorted it :)

[nilsonneto]

@RossFleming - please add an answer and accept it by clicking the tick button next to the answer. Thank-you.

[Estifan Panosian]

I have installed Ubuntu 14.04 and encountered the same problem with my Lenovo x61, with the same network card: Intel Corporation PRO/Wireless 4965 AG or AGN [Kedron] Network Connection. Does it mean the problem is still not solved? Shall I disable "n"? thank you, EPA