Notice
RF-KILL
bluetoothctl
PAN

Notice, this way is only for Bluez-5!!!!

Refers to:

https://wiki.gentoo.org/wiki/Bluetooth_Network_Aggregation_Point
https://wiki.gentoo.org/wiki/Bluetooth
http://blog.fraggod.net/2015/03/28/bluetooth-pan-network-setup-with-bluez-5x.html

Bluez-4 could be much more easier via pand. For example, in ubuntu you could setup the bluetooth PAN via:

http://blog.sumostyle.net/2009/11/ubuntu-tethering-via-bluetooth-pan/

Use rfkill for unblock the soft-blocked bluetooth adapter:

[root@xxxx dash]# rfkill list bluetooth
2: hp-bluetooth: Bluetooth
        Soft blocked: yes
        Hard blocked: no
5: hci1: Bluetooth
        Soft blocked: yes
        Hard blocked: no
[root@xxxx dash]# rfkill unblock bluetooth

# rfkill list bluetooth
2: hp-bluetooth: Bluetooth
        Soft blocked: no
        Hard blocked: no
5: hci1: Bluetooth
        Soft blocked: no
        Hard blocked: no

Use bluetoothctl for configurating the bluetooth adapter:

[root@xxxx ]# bluetoothctl 
[NEW] Controller 40:2C:xx:xx:xx:xx xxxx #2 [default]
[bluetooth]# power on
Changing power on succeeded
[bluetooth]# discoverable on
Changing discoverable on succeeded
[bluetooth]# agent on
Agent registered
[bluetooth]# scan on

Refers to:
http://blog.fraggod.net/2015/03/28/bluetooth-pan-network-setup-with-bluez-5x.html

--- machine-1
% bluetoothctl
[NEW] Controller 00:02:72:XX:XX:XX malediction [default]
[bluetooth]# power on
Changing power on succeeded
[CHG] Controller 00:02:72:XX:XX:XX Powered: yes
[bluetooth]# discoverable on
Changing discoverable on succeeded
[CHG] Controller 00:02:72:XX:XX:XX Discoverable: yes
[bluetooth]# agent on
...

--- machine-2 (snipped)
% bluetoothctl
[NEW] Controller 00:02:72:YY:YY:YY rpbox [default]
[bluetooth]# power on
[bluetooth]# scan on
[bluetooth]# agent on
[bluetooth]# pair 00:02:72:XX:XX:XX
[bluetooth]# trust 00:02:72:XX:XX:XX

Then Download the script from:

https://github.com/mk-fg/fgtk/blob/master/bt-pan

This bt-pan will setup both the server and the client.

In Server:

$ bt-pan --debug server $br

While the $br could be setup via following command(Take Gentoo for example):

# vim /etc/conf.d/net

...
# Comment out this line, and add the following lines:
#config_eth0="dhcp"
config_eth0="null"
bridge_br1="eth0"
config_br1="dhcp"
# Next two lines, to make two values work (keep setfd before stp):
brctl_br1="setfd 1
stp on"
...
# ln -s net.lo /etc/init.d/net.br1
# rc-service net.eth0 stop && rc-service net.br1 start
# rc-update add net.br1 default 

In the Client side, do following:

$ bt-pan client 00:02:72:XX:XX:XX

Now check the both client and server, you will find bnep0 interface has been created, you could see it via ifconfig bnep0.

Assign the same IP network range address to the client side, as in the br1 side in server. After that you could ping each other via bluetooth!