[clug-talk] networking question

[Robert Lewko]

I have been tasked with getting performance information with a Sierra
Wireless Aircard 595.  I have a program that I have written that gives
me signal strength (I wrote it with info under an NDA to SW).

I am using ppp to create a network connection on a Linux box.  Then I
establish a VPN with openvpn.  I can test the VPN by pinging
192.168.10.1.  Then I run a daemonized iperf on 192.168.10.1.  How I
start it is like this:

iperf --bind 192.168.10.1 -s -D

Then I attempt to run iperf on the client to get a two way performance
test - like so:

iperf -c 192.168.10.1 -d -r

A correct run looks like this (done on my home network):

nomad at trinity:/etc/openvpn$ iperf -c 192.168.1.50 -d -r
------------------------------------------------------------
Server listening on TCP port 5001
TCP window size: 85.3 KByte (default)
------------------------------------------------------------
------------------------------------------------------------
Client connecting to 192.168.1.50, TCP port 5001
TCP window size: 22.6 KByte (default)
------------------------------------------------------------
[  5] local 192.168.1.101 port 34793 connected with 192.168.1.50 port 5001
[  5]  0.0-10.0 sec  24.4 MBytes  20.5 Mbits/sec
[  4] local 192.168.1.101 port 5001 connected with 192.168.1.50 port 57159
[  4]  0.0-10.0 sec  27.3 MBytes  22.8 Mbits/sec
nomad at trinity:/etc/openvpn$

I get a VPN established.  If I create the VPN on my home Shaw network
then I get all the routes that the VPN normally creates,  If I use the
Aircard, then I should have a route like "nn.nn.nn.nn via 192.168.1.1
dev ath0", but the VPN does not create that route.  Secondly, when I
do the iperf test the vpn collapses after the first part of the test
is done, the return performance test never completes.

Here is how that looks on the screen.

nomad at trinity:/etc/openvpn$ iperf -c 192.168.10.1 -d -r
------------------------------------------------------------
Server listening on TCP port 5001
TCP window size: 85.3 KByte (default)
------------------------------------------------------------
------------------------------------------------------------
Client connecting to 192.168.10.1, TCP port 5001
TCP window size: 16.0 KByte (default)
------------------------------------------------------------
[  5] local 192.168.54.18 port 32815 connected with 192.168.10.1 port 5001
[  5]  0.0-10.0 sec  1.13 MBytes    949 Kbits/sec

and it hangs forever.

I am using Kubuntu 8.04 and I have tried Kubuntu 8.10.  I have also
tried killing KNetworkManager 'cause I have heard that it interferes
with the server's "push" routes.  I have also turned
off window_scaling.  I am going to try Debian Lenny.

Can you guys think of anything so that I can get this working.