Android Tether - When the Linux Laptop won't connect to WiFi but the Phone does

Linux users and the age old WiFi problem

A Linux die-hard, who'd rather distro-hop, than run any non-Linux based OS. After spending hours trying to figure it out, managed to get the problematic WiFi module to work with the home WiFi router. The laptop connects reliably to the Internet. Life is bliss. Or it is, until the fateful visit with the laptop to a friends or relative's place, a hotel room, or a local coffee shop, that has graciously allowed its patrons to use the Internet connection over WiFi, and the Laptop refuses to connect to the WiFi.

For best impact read the above again, this time in Rod Sterling's voice, like the opening from "The Twilight Zone".

Those familiar with this scenario can feel the frustration one goes through in this situation. I've gone through it many times over the years, and recently, my wife had to as well. The biggest cause for this is that, majority of WiFi modules that are packaged with laptops these days, come with little or no manufacturer support under Linux. That is the unfortunate state of WiFi networking under Linux.

For situations like this, I started carrying with me a USB WiFi module known to work under Linux, as a fail-safe. I sacrifice bandwidth for reliability and it has proved useful over the years. The flip side of this was that, the Android phones I've used over the years, always connected successfully to almost any WiFi network, and I could reliably access Internet over them.

The irony of the situation was that, the solution to my problem was in my pocket all this time, if only I had cared to check it there.  

Android Phone comes to the rescue

Almost all modern Android phones natively provide multiple forms of tethering options: WiFi tethering, USB tethering, and Bluetooth tethering. The good news is, some of these options could come in handy when faced with the WiFi connectivity problems.

WiFi Tethering

WiFi Tethering allows you to share your phone's data connection (3g, 4g, LTE, etc.) with computers that are within range, over WiFi. It transforms your phone into a WiFi Hotspot. The problem with this approach is, you are burning through your phone's data, which doesn't come cheap. Many carriers also impose additional charges to even allow data sharing over WiFi.

USB Tethering

This one took me by surprise. I had used USB tethering before; to share my phone's data connection with my laptops. Setting it up used to be more involved, requiring running a few commands, but newer Android phones have made it seamless to the point, where, it only requires one to check a checkbox on their phone, to activate it. What I hadn't thought of, or tested, earlier was that I could use USB tethering to even share the network that the phone was accessing over its WiFi connection. You do need a data capable USB cable for this to work. You'll know if your USB cable is data capable, if your laptop identifies your phone, and the phone identifies that it is connected to a computer.

Using this option, you'll be able to access your phone's Internet connection over a USB cable connected to you laptop. The connection speed will vary depending on your laptop and the phone capabilities. I was able to get nearly 15Mbps downloads and around 5.5Mbps uploads using this approach with my Nexus 5 phone.

Bluetooth Tethering

Modern laptops are shipping with WiFi modules that also have a Bluetooth radio. This allows the users to share files with other paired Bluetooth devices, as well as, do some other fancy Bluetooth things. For instance, I can pair my phone with my laptop over Bluetooth, and then all of my phone's sound notifications and other media playing, can be heard on my laptop. Another thing you can do over Bluetooth is share the Internet connection.

Like the earlier two options, you can extend your phone's data connection to the paired device. You may incur additional charges, but it is good to know you have that as an option. You could also, like with the USB tethering option, share your phone's WiFi network connection over to the paired devices - in this case, your Bluetooth enabled laptop.

Don't expect phenomenal speeds. This is Bluetooth we are talking about. My TWC Internet connection clocks nearly 20Mbps over WiFi. But when tethered over my phone's Bluetooth, it drops to mere 0.6Mbps. It's still better than your laptop's WiFi if it doesn't connect at all.

Initial issues with Bluetooth Networking

One issue I ran into, while attempting to setup Bluetooth tethering, was that, while the laptop identified the phone's Bluetooth network, and I could transfer files back and forth over Bluetooth, I wasn't able to connect to the Bluetooth network on my phone. Network Manager would show "configuring network interface" message, but always failed to connect.

I later realized that somehow the default configuration of the Bluetooth pair on my phone was interfering with this. The paired connection on my phone, for the laptop, did not expose "Internet Connection Sharing", as an option. I only saw "Media audio" and "Contact sharing", and both were checked. When I unchecked "Media audio" and tried to connect to the Bluetooth network "Nexus 5 Network" from my laptop, I was able to connect to the network. Checking the paired connection's option again on my phone revealed the a new checkbox option, "Internet Connection Sharing", which was already checked.

The Verdict

If you are on the go, with a laptop containing an unreliable WiFi module, you do have options. As long as you have an Android phone (only tested with an Android phone) and a USB data cable or a Bluetooth module for you laptop, you'll be able to stay connected. Of the two, USB tethering offers superior connections speeds, but Bluetooth tether offers yet another fail-safe in case you don't have a data capable USB cable with you. While you may not be able to reliably stream videos from YouTube or Netflix over Bluetooth, as with everything else Linux, it is yet another option.

How I learned to program in Scala: The Nexus 5 experiment

Few months back I broke up my long term affair with Mono and I started looking into the the Play Framework from TypeSafe as a replacement stack.

Through Play Framework, I discovered Scala and the wonders of functional programming. My interest grew even deeper when I installed Scala on my laptop and tried some example code in the REPL tool (think Scala interactive shell).

However, I found very soon that I was not able to dedicate enough time during the week to learning Scala due to my full time day job doing .Net development.

Something had to be done.

I thought, I have this wonderfully powerful device on me all the time - my Nexus 5. Surely, I should be able to put it to use to help me spend more time with Scala. So began the experiment.

I rooted my Nexus 5, installed "Linux Deploy" from Google Play Store and installed a chroot Arch Linux environment. I also installed JuiceSSH client and a VNC viewer application. I already had "Terminal IDE" installed which comes with a great android keyboard geared towards software development on Android.

The last piece to the puzzle, I bought a $25 ANKER bluetooth keyboard compatible with my Nexus 5.

I fired up the Arch chroot on my phone, downloaded tmux and vim using pacman and oracle java 7 packages from AUR (some PKGBUILD tweeking was needed).

Then I installed TypeSafe Activator from AUR. I also downloaded vim plugins like vim-scala and CtrlP which proved to be of great help.

It worked!!!

Using the setup described above, I was able to not only learn how to program Scala, I am also able to write software using Play Framework. I can test the same on my phone's browser. The code is backed up on github and I can work on the same codebase from anywhere - as long as I have my Nexus 5 and data connection.

And after the recent KitKat update with Cast Screen - I am able to cast my phone's screen to my big screen HD TV over ChromeCast. This solves the issue of developing on the relatively small Nexus 5 screen.

This experience has made me appreciate VIM, TMUX, and the terminal in general at a whole new level. Even when on my laptop, I now find myself doing more and more coding in VIM instead of IntelliJ.

Think about it, you can now get a decent android box or even a phone, and with a setup similar to what I described, have an almost full fledged development environment. Rich graphical applications can be written in Scala using Swing (sigh) and possibly other graphical toolkits and can be tested within the Arch (or other Linux distro) chroot using VNC.

Side note about Oracle Java instead of OpenJDK: I went with Oracle Java instead of OpenJDK due to an "issue" with OpenJDK on arm chips. Its something to do with JVM running in "mixed mode".

"Operator. How may I direct your call?"

Disclaimer: Flying through Linux and OpenSource. You might experience Freedom along with plenty of awesomeness.

I am a curious being and I love the freedom that is offered by Linux. Because of this, you will occasionally find me spending hours on pet projects that have nothing to do with what I do for a living.

In past couple posts, I shared my desire and my efforts to set up my own PBX in my home network. I also shared the discussion I had with a colleague who had successfully setup an intercom system that he used to talk with his family abroad. After spending numerous hours on this feat over past few days, last night I finished my setup and I now have all the functionality that I needed from this setup.

I installed FreeSWITCH on a Debian server that I have on my home network. It had to be compiled from source since PogoPlug houses an ARM processor and Debian repositories didn't have a packages for FreeSWITCH for arm architecture. But the instructions were easily available and installation was a piece of cake. Like I had mentioned in the previous post, the installation came pre-configured with 20 extensions for internal use, an demo IVR menu, and plenty of other features.

I was now able to register soft phone softwares running on our Linux desktops and laptops and my Android phone over WiFi within our home network and test the calling from one soft phone extension to another.
I now needed a sip gateway router that would allow me to connect my home phone line to the FreeSWITCH setup. I found a great deal on a Cisco/Linksys SPA 3102 sip gateway router. SPA 3102 allowed me to connect my incoming phone line on one jack and my home phone unit on the other.
I now had a PBX setup which was accessible to be via the home network for internal calling. I was also connected to my home phone line, which allowed me to make outbound calls and receive incoming calls.
Now one thing to keep in mind that even though SPA 3102 has a jack for phone line (FXO) and a jack to connect a physical phone (FXS) they operate on two separate extensions. However, now that we are in SIP/PBX territory, calls can be bridged and transferred from one extension to another. I was able to configure FreeSWITCH and SPA 3102 so that the calls received on the PSTN line (FXS) would be forwarded to Line 1 (FXO) where my phone was attached. I also configured FreeSWITCH to send the calls originating on internal extensions - Line 1 on SPA 3102 also being one of them - that are not handled internally, to send them outbound via PSTN line. My basic phone setup was restored and I now had the capability to make outbound calls from any computer from within my home network. Think Skype Out without paying an addition cent.

I mentioned earlier that I was able to register and test soft phone on my Android phone to my home FreeSWITCH server. This was done over WiFi. I was able to open ports on my home firewall for FreeSWITCH so that I could connect from an outside network. And I was successfully able to test this by getting on a different WiFi network that had Internet access. The next thing naturally was to do a quick test over 3G we'd be in business. Yeah, right. This was not as quick as I had anticipated it to be. I was able to originate outbound calls and receive incoming calls successfully, but there was no audio. After spending hours researching it, I found the answer hidden in plain sight, mocking me all this time.

SIP Servers and phones use what is called a STUN service to help with port discovery when connecting to other servers and phones behind NAT/firewall. I had already read about it briefly and had configured my server to use stun.freeswitch.org as the STUN service url. From the reviewing the logs, I discovered that the url was not reliable and down most of the time. There are however a number of free STUN services available and I found a webpage that listed quiet a few of those. FreeSWITCH comes with a STUN server testing utility and I was able to find one of the STUN servers that was indeed online. I configured my FreeSWITCH server to use it, and now I had audio on my Android phone over 3G.

All this was a fun and exciting experience overall. Besides the time I put in it, it cost me $43 that I paid for the SPA 3102. What are the practical applications you'd ask. There are plenty, and I plan to dedicate the next article discussing those.

Progress on this topic can be following in the following articles:

PogoDebian + FreeSWITCH + Linksys 3102 VoIP Gateway = Pure Bliss - Part 1

Hello!!! We have a dial tone.

"Operator. How may I direct your call?"

FreeSWITCH Implementation ideas