Ubuntu 12.04 hotspot wifi network not visible to Android 4.1.2

Question

I'm running Ubuntu 12.04 LTS on my notebook, and I've got a Motorola Razr which I updated to Android 4.1.2. Before updating, I connected my smartphone to my hotspot wifi very quickly, but after the update it no longer works. Android 4.1.2 can't see the hotspot created by Ubuntu; it sees all other wifi networks and can connect to them, but not mine. What could be wrong?

Answer 1

You can use ap-hotspot from the webupd8 repository to create an infrastracture AP instead of adhoc. I am using this on Ubuntu Precise (12.04), but it is available for Saucy, Raring and Quantal as well.

$ sudo su -
# add-apt-repository ppa:nilarimogard/webupd8
# aptitude update
# aptitude install ap-hotspot
# ap-hotspot configure
# ap-hotspot start

Answer 2

Follow the steps to create detectable hotspot in Ubuntu:

1. To install hostapd just type this command on the terminal:

   sudo apt-get install hostapd
   

2. Then, open a text editor program, for example, gedit. Copy the following into it.

   interface=wlan0
   driver=nl80211
   ssid=MyAP
   hw_mode=g
   channel=11
   wpa=1
   wpa_passphrase=MyPasswordHere
   wpa_key_mgmt=WPA-PSK
   wpa_pairwise=TKIP CCMP
   wpa_ptk_rekey=600
   

3. Please don’t forget to fill in the name of your network after ssid=, as well as the password after wpa_passphrase=.

4. After all these, save the file as hostapd.conf in your home folder.

5. Then create a normal ad-hoc network from the wireless menu from the top bar click on “Create New Wireless Network“

6. After the new network created successfully proceed to the next and the final step

   Now, in your terminal:

   sudo hostapd hostapd.conf
   

   Turn the wifi connection on in your devices and enjoy the fast network share!

Answer 3

There are 2 things you need to make sure you have configured correctly. The WIFI hotspot on Ubuntu and your Android device's ability to connect to an ad-hoc hotspot.

Setting up WIFI ad-hoc on computer

This tutorial covers getting your ad-hoc, titled: How to set up Ubuntu 12.04 laptop as WiFi hotspot (ad-hoc) to share wired internet. In general you need to setup a WIFI hotspot under "Edit Connections -> Add" similar to the screenshot below:

                

Then specify your wireless security settings similar to the following screenshot:

                

Make sure it's set with the following options:

• “WEP 40/128-bit Key (Hex or ASCII)”
• make the length of the key 5 characters

Under the “IPv4-Settings” tab, choose the option “Shared to other computers” for “Method”.

Setting up Android ad-hoc

According to this thread over on the Ubuntu Forums titled: Hotspot is not visible on other devices (12.04 precise), you need to follow this tutorial. It's reported to work for HTC Sensation 4G devices but might work for Motorial Razr. These are patches so YMMV.