How to setup a PPP connection between an Android smartphone and a Linux computer? For testing purposes, I need to connect an Android smartphone to my Linux desktop computer to enable communication between the phone and some servers on the LAN. I can't use Wi-Fi so I'm stuck with IP over USB.

So my question is: How to connect the smartphone to my computer?

If you know something else than PPP, please let me know. This is what i've tried for the moment:

root@desktop:/# adb ppp "shell:pppd nodetach noauth noipdefault defaultroute /dev/tty" nodetach noauth noipdefault notty 10.0.0.1:10.0.0.2
root@desktop:/#


As you can see, this command doesn't output anything...
I guessed I should see a new ppp0 interface show up on my destkop if it worked (am I right?), but nothing happens actually.

So I thought it could be because I was lacking the root privilege, and I tried the following:

root@desktop:/# adb root
adbd cannot run as root in production builds
root@desktop:/#


FYI, when I run the adb shell command I'm not logged in as root:

root@desktop:/# adb shell
$ whoami
whoami: unknown uid 2000
$ su
# whoami
whoami: unknown uid 0
#


EDIT: I tried on a phone running CyanogenMod 10.2: the adb root command is successful, but adb ppp ... doesn't output anything. No ppp0 interface shows up on my computer.
I also forgot to say I'm running Ubuntu 12.04 on the desktop computer if it can help finding the problem.

So, what's next? Do you think I need a different kernel? Did I miss something regarding the way to bring up a PPP connection?
Try this:

adb ppp "shell:/system/bin/su -c 'pppd nodetach noauth noipdefault defaultroute /dev/tty'" nodetach noauth noipdefault notty 10.0.0.1:10.0.0.2