ndt-users list created

[Larry Vaden <>]

Rich,

Thanks for your reply ... I will test against the measurementlab.org
servers when I am home this evening.  The dry DSL connection is a
backup to my wireless connection to the NOC in the event a
thunderstorm takes out the wireless.

Thanks for such a GREAT tool as NDT.

kind regards/ldv

On Tue, Nov 2, 2010 at 9:03 AM, Rich Carlson 
<>
 wrote:
> Larry;
>
> A couple of months ago I found that tests were timing out and failing after
> the C2S test.  The problem turned out to be a bug in the applet code.
>  Specifically, Java uses blocking I/O calls and the client would enter a
> write state (I/O call), but the server closed the connection due to a
> timeout.  The result was that the client would hang, and the S2C test would
> fail.
>
> This bug was fixed in v3.6.4.  The ANL and USCS servers both pre-date this
> version.  (Yes, I know the version numbers are higher, but that's another
> story).
>
> One way to verify that 3.6.4 does fix this problem is to test against one of
> the measurementlab.org servers
> http://www.measurementlab.org/measurement-lab-tools#tool1
>
> Rich
>
> On 11/2/2010 5:13 AM, Larry Vaden wrote:
>>
>> Hello NDT-users,
>>
>> The test is performed against ndt.anl.gov:7123 and fails;  the test
>> does not fail when performed against ndt.ucsc.edu:7123.
>>
>> Verizon dry DSL --- ActionTec GT704WGB dsl modem --- MikroTik RB750
>> --- XP laptop
>>
>> The ActionTec obtains a public IP address from Verizon.
>>
>> The MikroTik diverts only RFC1918 space via L2TP tunnel to our network
>> (texoma.net, ASN 4963).
>>
>> Everything seems to function OK (public address space, RFC1918 address
>> space suffers ~ 2 msec latency).
>>
>> NDT takes ~ 2 min to complete the 10 second C2S test, then has
>> problems with the S2C test.
>>
>> Double NATing is occurring.
>>
>> Is this likely a cockpit error on my part?
>>
>> THANKS for such a great tool --- we use it often to find problems in
>> our rural wireless network.
>>
>> kind regards/ldv
>>
>> Larry Vaden, CoFounder
>> Internet Texoma, Inc.
>> Serving Rural Texomaland Since 1995
>> We Care About Your Connection!
>>
>> ===== testing against ndt.internet2.edu
>>
>> TCP/Web100 Network Diagnostic Tool v5.5.4b
>> click START to begin
>>
>> ** Starting test 1 of 1 **
>> Connected to: ndt.anl.gov  --  Using IPv4 address
>> Checking for Middleboxes . . . . . . . . . . . . . . . . . .  Done
>> checking for firewalls . . . . . . . . . . . . . . . . . . .  Done
>> running 10s outbound test (client-to-server [C2S]) . . . . . 370.0kb/s
>> running 10s inbound test (server-to-client [S2C]) . . . . . . Protocol
>> error!
>> S2C throughput test FAILED!
>> Protocol error!
>>
>> click START to re-test
>>
>> ** Starting test 1 of 1 **
>> Connected to: ndt.anl.gov  --  Using IPv4 address
>> Another client is currently being served, your test will begin within
>> 135 seconds
>> Another client is currently being served, your test will begin within 90
>> seconds
>> Another client is currently being served, your test will begin within 45
>> seconds
>> Checking for Middleboxes . . . . . . . . . . . . . . . . . .  Done
>> checking for firewalls . . . . . . . . . . . . . . . . . . .  Done
>> running 10s outbound test (client-to-server [C2S]) . . . . . 371.0kb/s
>> Error in parsing tests results!
>>
>> click START to re-test
>>
>> ===== testing against ndt.ucsc.edu:7123
>>
>>
>> TCP/Web100 Network Diagnostic Tool v5.5.4a
>> click START to begin
>>
>> ** Starting test 1 of 1 **
>> Connected to: ndt.ucsc.edu  --  Using IPv4 address
>> Checking for Middleboxes . . . . . . . . . . . . . . . . . .  Done
>> checking for firewalls . . . . . . . . . . . . . . . . . . .  Done
>> running 10s outbound test (client-to-server [C2S]) . . . . . 372.0kb/s
>> running 10s inbound test (server-to-client [S2C]) . . . . . . 760.80kb/s
>> Your PC is connected to a Cable/DSL modem
>>  [S2C]: Packet queuing detected
>>
>> click START to re-test
>>
>