Debian-Tethering

This article documents how to setup Debian for tethering to an N900. How to setup the N900 is described in the Bluetooth DUN article.

Setup Bluetooth connectivity

Installing required Debian packages

apt-get install bluez-utils pppconfig

Setting Up Bluetooth Connectivity

blackbox:~# hcitool scan
Scanning ...
  11:22:33:44:55:66       Nokia N900
blackbox:~# sdptool browse 11:22:33:44:55:66

Search for the Dial-Up Networking service

blackbox:~# sdptool browse 11:22:33:44:55:66
Browsing 11:22:33:44:55:66 ...
[...]

Service Name: Dial-Up Networking
Service RecHandle: 0x10005
Service Class ID List:
  "Dialup Networking" (0x1103)
  "Generic Networking" (0x1201)
Protocol Descriptor List:
  "L2CAP" (0x0100)
  "RFCOMM" (0x0003)
    Channel: 1
Profile Descriptor List:
  "Dialup Networking" (0x1103)
    Version: 0x0100

[...]

blackbox:~#

Add an rfcomm device (e.g. rfcomm0) to /etc/bluetooth/rfcomm.conf (make sure to replace the Bluetooth device address 11:22:33:44:55:66 with the Bluetooth device address of your N900):

/etc/bluetooth/rfcomm.conf
rfcomm0 {
#       # Automatically bind the device at startup
        bind yes;
#
#       # Bluetooth address of the device
        device 11:22:33:44:55:66;
#
#       # RFCOMM channel for the connection (whatever you get from the sdptool output)
        channel 1;
#
#       # Description of the connection
        comment "N900";
}

Restart the bluetooth stack:

blackbox:~# /etc/init.d/bluetooth restart

For bluetooth pairing you can run

blackbox:~# cat < /dev/rfcomm0

and first the N900 then the Debian system should ask you for a 4 digit PIN which you define on the N900 and confirm on the Debian system. You might have to configure the helper application which is using the PIN in /etc/bluetooth/hcid.conf

Dial-Up Settings

Run pppconfig and use /dev/rfcomm0 as the modem interface:

In my settings for klarmobil (Germany) I manually added two lines (at+cdgcont=... and AT+CREG...):

blackbox:~# cat /etc/chatscripts/klarmobil
# This chatfile was generated by pppconfig 2.3.18.
# Please do not delete any of the comments.  Pppconfig needs them.
#
# ispauth PAP
# abortstring
ABORT BUSY ABORT 'NO CARRIER' ABORT VOICE ABORT 'NO DIALTONE' ABORT 'NO DIAL TONE' ABORT 'NO ANSWER' ABORT DELAYED
# modeminit
 ATZ
# ispnumber
OK at+cgdcont=1,"IP","internet.t-mobile","",0,0
OK AT+CREG=2
OK-AT-OK "ATDT*99#"
# ispconnect
CONNECT \d\c
# prelogin 
 
# ispname
# isppassword
# postlogin
 
# end of pppconfig stuff
blackbox:~#

In my peers file I changed the baud rate to the device

blackbox:~# cat /etc/ppp/peers/klarmobil
# This optionfile was generated by pppconfig 2.3.18.
#
#
hide-password
noauth
connect "/usr/sbin/chat -v -f /etc/chatscripts/klarmobil"
debug
/dev/rfcomm0
#460800
921600
defaultroute
noipdefault
user "tm"
remotename klarmobil
ipparam klarmobil 

usepeerdns
blackbox:~#

For ifupdown integration add to /etc/network/interfaces

iface ppp0 inet ppp
 provider klarmobil

Details are in the Debian Reference.