Hi to all:
I got a second Nanonote this week, just in case my first one breaks
down. I spent several hours experimenting on how to connect more than
one Nanonote to a single computer. There were quite a few dead ends,
confusions, and foggy moments but I finally got something to work. I
am no expert in the rather arcane world of gateways, routes, and more
that come into play. I followed what worked for one Nanonote and
tried various adjustments to get it working for two Nanonotes.
Important: All of my desktop or servers run Debian. I am now on
Debian Wheezy on my desktops. I suspect there will be some
differences with other distributions. Also all work is done
as root on the host machine. sudo would also work, I suspect,
if its config file is setup properly.
I have two nanonotes. One will have the host name of: "nn" and the
other the host name of "nm". Also, I always work from Micro SD cards
so that the host name really goes with the SD card:)
1. After some trial and error I discovered that each Nanonote is
assigned a unique usb designation when it is connected to the
host computer. The first Nanonote to be connected
to the host computer will get: usb0, the next will get: usb1. I
assume, but cannot test, that the third Nanonote would get: usb2.
Thus with two Nanonotes connected to a computer, a review of the end
of /var/log/kern.log, would show both usb0 and usb1 being active.
Note: I have sometimes had the second connection fail. So it is
useful to run
tail -f -n 30 /var/log/kern.log
to see what the kernel "thinks" about the connection. If it fails,
unplug the usb cable and then plug it in again. I'm not sure why this
happens but it has happened more than once so far.
2. Decide what private network will apply to each of the nanonotes.
They must differ. Of course private networks are cheap:) I tried
various ways to use one private network but could not get it to work.
Here is what I did.
Nanonote gateway ip address nanonote ip address
nn 192.168.254.100 192.168.254.101
nm 192.168.253.100 192.168.253.101
On the host computer, that is the one to which the Nanonotes are
connected via usb cables:
2.1 Edit /etc/hosts and add both ip addresses for the Nanonotes
192.168.254.101 nn
192.168.253.101 nm
This just makes it easier to refer to them.
2.2 Add the following to the .bashrc file, or the equivalent
for other shells:
export nn=192.168.254
export nm=192.168.253
These environmental variables will be used to make
connecting a bit more convenient. There is no conflict
between "nn" as a host name and "nn" as an environmental
variable.
3. Construct a script on the host machine that contains the
following:
#!/bin/sh
echo usb$1 $2
ifconfig usb$1 $2.100
iptables -A POSTROUTING -t nat -j MASQUERADE -s $2.0/24
sysctl -w net.ipv4.ip_forward=1
route add -host $2.101 usb$1
In my case the file name of the script was: nano_connect
This script has two command line arguments. The first argument is the
number of the usb device assigned to that nanonote. The second
argument will be the environmental variable that gives all but the
last field of the static UP address of the Nanonote being connected.
To connect Nanonote nn to the host, execute
nano_connect 0 $nn
Connecting Nanonote nm to the host after connecting Nanonote nn
requires
nano_connect 1 $nm
We can connect the Nanonotes in any order or just connect one and the
proper choice of arguments to the nano_connect script makes it all
work.
4. Before this works we have to add some information to the
/etc/config/network file on each Nanonote.
For Nanonote nn, the network file looks like this:
config interface loopback
option ifname lo
option proto static
option ipaddr 127.0.0.1
option netmask 255.0.0.0
config interface lan
option ifname usb0
option proto static
option ipaddr 192.168.254.101
option netmask 255.255.255.0
option gateway 192.168.254.100
option 'dns' '208.201.224.xx 208.201.224.xx 192.168.1.1'
The last line defines the DNS's to use. I use the servers from my ISP
followed by the DNS for my LAN. Note that the IP address for the LAN
must be the last entry in the list for this to work. In some earlier
versions of OpenWRT, the local LAN entry had to be first:) The default
contents of the network file are the same as this, as I recall, except
for the DNS option line.
For Nanonote nm, the network file is almost the same.
config interface loopback
option ifname lo
option proto static
option ipaddr 127.0.0.1
option netmask 255.0.0.0
config interface lan
option ifname usb0
option proto static
option ipaddr 192.168.253.101
option netmask 255.255.255.0
option gateway 192.168.253.100
option 'dns' '208.201.224.xx 208.201.224.xx 192.168.1.1'
The only difference is that the .254. becomes .253.
Notice that the "option ifname" is usb0 because there is only one
interface from each Nanonote. There are two interfaces for the host
computer. This confused me at first. I thought that the second
Nanonote should have usb1 to match the usb1 on the host. This turned
out to be faulty thinking. The USB designations are local to each
machine and only depend on the number of connections being made on
each machine. The critical part is that the IP addresses match.
5. To finally make the connection complete, run
/etc/init.d/network restart
to restart the networking software on each Nanonote connected to the
host machine. To save typing on the Nanonote keyboard, I create a
script called "connect" that contains:
#!/bin/sh
/etc/init.d/network restart
6. The final item needed is to enable access to the Nanonotes
from machines, other than the host machine, on my LAN. To do
that create a script called "nano_add"
#!/bin/sh
#Delete old route-ip address may have changed
route del -net $1.0/24
#Add a route to ac to access nanonotes
route add -net $1.0 netmask 255.255.255.0 gw $2 eth0
This script has two arguments: The first is the environmental variable
for each nanonote and the second is the machine name of the host for
the Nanonotes. For example, I have a netbook, called "ac" that is
used to interface to the Nanonotes. Then on another machine, say,
i7, my main desktop, I would execute
nano_add $nn ac
so that I could access Nanonote nn from i7. To access Nanonote
nm
nano_add $nm ac
There is probably a more streamlined method than this one but for now,
what I have works, and is flexible enough that I can connect one or
two Nanonotes in any order and on any machine in my LAN so long as I
carefully define the contents of the /etc/hosts file as well as the
environmental variables for the Nanonotes.
Thanks to Xiangfu Liu for the original scripts that worked for connecting
one Nanonote. I just modified those in various ways to get something
going for two Nanonotes.
Hope this helps someone else.
Delbert
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