Developer Forum

ello All,

Sorry for the verbosity of this post...

I am trying to set up an ad-hoc wireless network between two
computers; one runing Windows XP and the other Linux (2.6.x,
Slackware).
After I have set them up I cannot ping the Linux machine from the
Windows machine.

This is what I have done so far:

* Made sure that the Wlan card is running on the Linux machine
(it is; it's a RT61 based D-Link DWL-G510). It works fine when in
"managed" mode (connecting to an access-point); I'm using the latest
firmware/drivers I could find.
* Made sure that the Wlan card is running on the Windows machine
(it is; Intel something-something built into a Dell laptop).

Then I try to set things up.

** On the Linux machine:

$ modprobe rt61 (load module, card is recognized)
$ iwconfig ra0 essid box (ra0 is my RT61, set SSID)
$ iwconfig ra0 channel 11 (we are in Europe)
$ iwconfig mode Ad-Hoc (this is what I want; no encryption)
$ ifconfig eth0 down (just in case; remember ra0 is the WLan
card)
$ ifconfig ra0 10.0.0.1 netmask 255.255.255.0 up (interface comes up)

$ ifconfig ra0
ra0 Link encap:Ethernet HWaddr 00:19:5B:70:2D:D2
inet addr:10.0.0.1 Bcast:10.0.0.255 Mask:255.255.255.0
inet6 addr: fe80::219:5bff:fe70:2dd2/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:3 errors:0 dropped:0 overruns:0 frame:0
TX packets:7 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:192 (192.0 b) TX bytes:468 (468.0 b)
Interrupt:10

$ iwconfig ra0
ra0 RT61 Wireless ESSID:"" Nickname:""
Mode:Ad-Hoc Frequency:2.462 GHz Cell: 66:9F:2C:DA:89:A7
Bit Rate=54 Mb/s
RTS thr:off Fragment thr:off
Encryption key:off
Link Quality=0/100 Signal level:-121 dBm Noise level:-99
dBm
Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:0 Invalid misc:0 Missed beacon:0
(note: the empty ESSID is normal. The card broadcasts the name
anyways)

$route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref
Use Iface
10.0.0.0 0.0.0.0 255.255.255.0 U 0 0
0 ra0
127.0.0.0 0.0.0.0 255.0.0.0 U 0 0
0 lo

From what I can see the "ra0" interface is up and running and it's
wating for an "Ad-hoc Handshake" or similar. We also have a
rudimentary routing table.

** Now I configure the Windows machine

* Enable Wireless (OK)
* In the network list I can see the "box" station configured on the
Linux machine.
* Tell the Wireless card to start an ad-hoc network with SSID "box"
on channel 11 with no encryption (it's "open")
* Set properties for the "wireless network connection" in the control
panel so it reads:

IP-address ........ 10.0.0.2
Netmask ........ 255.255.255.0
Standard gateway .. 10.0.0.1

After a few seconds I get a "green light" and Windows tells me I am
connected to the "box" network. Now the Windows machine has IP
10.0.0.2 with netmask 255.255.255.0 (ipconfig.exe confirms this).

Now: I still cannot ping the Linux machine (10.0.0.1 [255.255.255.0]).

I get no reports of connection problems. Still every ping times out.
Of course, when connected to an "ordinary" lan I can ping the Linux
machine from Windows without problems.

I suspect that I am

It looks like you didn't setup the routing on the linux box.

# route add default ra0
or
# route add default gw 10.0.0.2


There should be two ra0 entries. The second should be similar with the
Destination / Gateway entries swapped.

# route -n
# netstat -r

Beyond that it looks like you're setup/connected. Just that any pings
don't have a route to travel to return to the windows box. A ping from
the linux box to the windows box will likely give a no route to host
error. Or destination host unreachable. Assuming the firewall isn't
dropping them altogether.

Thank you for your suggestion:


I did add a default gateway but the problem persists.
The machine simply won't talk to each other over the ad-hoc link.

This is not limited to simply pingning the machines. I started proftpd
on the linux box and
tried to connect to it from windows:


but it won't (no response from server).


I know. Windows says the machines are connected (point-to-point) and
it's interface has
good values; still no packets from the Winbox arrives at the Linux
box.

Is there some special "thing" you have to do in Linux when setting up
an ad-hoc link in this fassion?

Regards

I haven't followed this thread,
but it might be worth setting one end - preferably the laptop -
to Managed, and the other to Ad-Hoc.

--
Timothy Murphy
e-mail (<80k only): tim /at/ birdsnest.maths.tcd.ie
tel: +353-86-2336090, +353-1-2842366
s-mail: School of Mathematics, Trinity College, Dublin 2, Ireland

Thanks:


but it did not help. Besides, the only way I could connect in this way
(managed to ad-hoc)
is by setting the ad-hoc card in "master" mode (so the card basically
pretends to be an
access-point device); but the linux software doest not support this.

I should mention that the network settings as such are sane. When I
"wire" the machines
to a small switch they behave perfectly (same settings as in original
post but substitute
ra0 for eth0).

The problem persists. Both machines say that the ad-hoc link is up but
no machine will talk to the other.

Regards /Tobias A

> Is there some special "thing" you have to do in Linux when setting up

I wouldn't say special thing. But obviously something you're missing.
Make sure the windows box is setup for TCP/IP and not just NetBeui(sp?).
And too little information has been provided.

Need outputs for linux from:

ifconfig -a

iwconfig

route -n

netstat -r

And depending on disto, contents of /etc/network/interfaces or other file.

For windows output for:

ipconfig /ALL

route PRINT

Something is missing in there. Or it might just be the firewall dropping
everything. I'm not sure why your wireless is ra0 though. Normally
that'd be wlan0, or eth# if your distro didn't account for wireless. I had
to change the udev rules to get mine to be wlan0. It was just too much
headache to try and remember which was wireless and which was ethernet,
eth0 or eth1.

I guess one should ask, not that you have the resources to check (multiple
machines multiple OS's). Can the windows box connect to other windows
box's? Can the linux box connect with other linux box's?

As far as AdHoc or Managed. Doesn't really matter. AdHoc is generally
for smaller networks and computer to computer connections. But it
can/will handle multiple connections. Managed just has a lot less
overhead on larger networks. In general if the connection is AdHoc, then
both machines should be set to that.

As far as default gateway. Try the default interface first. There can be
only one. One default that is. And unless the other box is setup with
NAT or ICS (windows), then it's not likely a gateway anyway. Not to
mention that 10.0.0.2 might not be it's address. With only 256x256x256x256
addresses to choose from. Technically 254 since 0 and 255 are special.

Does iwconfig say that ra0 has wireless extensions? If not, then you
probably need a wireless device driver. atmel, prism54, ndiswrapper,
wlan-ng, ???

gt; Make sure the windows box is setup for TCP/IP and not just NetBeui(sp?).

The winbox is set up to use TCP/IP.


eth0 Link encap:Ethernet HWaddr 00:40:63:EE:6E:C0
inet addr:192.168.0.163 Bcast:192.168.0.255 Mask:
255.255.255.0
BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:3013 errors:0 dropped:0 overruns:0 frame:0
TX packets:2177 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:281909 (275.3 KiB) TX bytes:311739 (304.4 KiB)
Interrupt:11 Base address:0xa000

lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:20 errors:0 dropped:0 overruns:0 frame:0
TX packets:20 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:1652 (1.6 KiB) TX bytes:1652 (1.6 KiB)

ra0 Link encap:Ethernet HWaddr 00:19:5B:70:2D:D2
inet addr:10.0.0.1 Bcast:10.0.0.255 Mask:255.255.255.0
inet6 addr: fe80::219:5bff:fe70:2dd2/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:7 errors:0 dropped:0 overruns:0 frame:0
TX packets:10 errors:1 dropped:1 overruns:0 carrier:0
collisions:2 txqueuelen:1000
RX bytes:376 (376.0 b) TX bytes:468 (468.0 b)
Interrupt:10



ra0 RT61 Wireless ESSID:"" Nickname:""
Mode:Ad-Hoc Frequency:2.462 GHz Cell: 7A:9F:32:50:B1:FA
Bit Rate=54 Mb/s
RTS thr:off Fragment thr:off
Encryption key:off
Link Quality=75/100 Signal level:-44 dBm Noise level:-100
dBm
Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:0 Invalid misc:0 Missed beacon:0


Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref
Use Iface
10.0.0.0 0.0.0.0 255.255.255.0 U 0 0
0 ra0
127.0.0.0 0.0.0.0 255.0.0.0 U 0 0
0 lo
0.0.0.0 10.0.0.2 0.0.0.0 UG 0 0
0 ra0


Kernel IP routing table
Destination Gateway Genmask Flags MSS Window
irtt Iface
10.0.0.0 * 255.255.255.0 U 0 0
0 ra0
loopback * 255.0.0.0 U 0 0
0 lo
default 10.0.0.2 0.0.0.0 UG 0 0
0 ra0


I will look this up (I'm running Slackware)


This will all be in swedish unfortunately but I think you can identify
the interesting settings for the wireless device anyways: it's at the
end "trl" means wireless and Nej=No, Ja=Yes.

IP-konfiguration f Windows

Vddatornamn . . . . . . . . . . : kg3
Primt DNS-suffix . . . . . . . :
Nodtyp . . . . . . . . . . . . . : Okd
IP-routning aktiverat . . . . . . : Nej
WINS-proxy aktiverat . . . . . . : Nej

Ethernet-kort Anslutning till lokalt nverk:

Medietillstd . . . . . . . . . . : Mediet frkopplat
Beskrivning . . . . . . . . . . . : Broadcom 440x 10/100
Integrated Controller
Fysisk adress . . . . . . . . . . : 00-15-C5-75-18-31

Ethernet-kort Trl nverksanslutning:

Anslutningsspecifika DNS-suffix . :
Beskrivning . . . . . . . . . . . : Dell Wireless 1370 - Mini-
P

I don't really understand your response.
Why can you not set your laptop card to Managed? eg with
sudo iwconfig ra0 mode Managed
Are there WiFi cards that don't support this mode?

I don't have great confidence that this will work -
but I don't see why it is not possible.

I used to run WiFi this way -
with a PCI WiFi card on my desktop in Ad-Hoc mode.
I found I had to set my laptop Orinoco PCMCIA card to Managed
for the connection to work.

However, I have used a LinkSys WR54GL access point for some years,
so the issue no longer arises for me.

Other suggestions: is there a firewall running on your Linux box?
Or on the Windows box?
Are you running NetworkManager?
What are the relevant entries in /var/log/messages on your laptop?





--
Timothy Murphy
e-mail (<80k only): tim /at/ birdsnest.maths.tcd.ie
tel: +353-86-2336090, +353-1-2842366
s-mail: School of Mathematics, Trinity College, Dublin 2, Ireland

> Why can you not set your laptop card to Managed? eg with

There are drivers and driver version(s) that only let you change a value
once. My broadcom cards used to have to have the essid set first,
otherwise you couldn't change it. Using the ndiswrapper driver of course.
But that was a long time ago. Things are better now, but I wouldn't say
perfect. I still have to set mode/rate/key off/essid with iwconfig before
running dhclient3 to connect to some wifi hotspots(McDonalds / Texas Rest
Stops). Especially those still on 802.11b. Sometimes I even have to set an
IP for myself before it'll let me connect using dhclient3(Texas Library).

> > sudo iwconfig ra0 mode Manag>d> > > Are there WiFi cards that don't support this mode?

Perhaps I should clarify. The wlan card on the Linuxbox can be set to
managed
mode yes but then the windows laptop refuse to make an ad-hoc
connection
to it. I must set both cards to "ad-hoc mode".

The problem persists. I'm thinking of getting a couple of cheap USB
bluetooth
adapters and setting up a network that way instead.

/Tobias a

I don't follow you.
I thought you didn't have a connection any time.


I doubt if that is wise.
I haven't read of many people setting up a Bluetooth LAN
and being happy with it.

I'm pretty sure your problem is solvable,
if you go through the possibilities.

Also, the fault may lie with the Windows machine.

1) Is there a Windows firewall running?

2? What relevant messages do you get in /var/log/messages
on your Linux machine?

3) Is NetworkManager running?
If it is, try turning it off.
If it isn't, try turning it on.

4) What does "iwlist ra0 scan" say?

--
Timothy Murphy
e-mail (<80k only): tim /at/ birdsnest.maths.tcd.ie
tel: +353-86-2336090, +353-1-2842366
s-mail: School of Mathematics, Trinity College, Dublin 2, Ireland

> 4) What does "iwlist ra0 scan" say?

iwlist ra0 scanning

And various other wireless-tools options to ID what the linux box does
see. I still think it's a routing issue. Windows or linux. A netmask of
255.255.255.255 means it can only talk to itself. A netmask of
255.255.255.0 means it can talk to any box with the first three numbers
matching. As long as that box is listening.

when you ping, what are you getting? no route to host? host unreachable?
or just 100% packet loss?