perfSONAR User Q&A and Other Discussion

[Daniel Bernardo <>]

Yes, twping localhost works, and knew it was running from the network capture seeing the session creation/ response process.

 

From the Network Capture done I was inclined to consider NAT the issue; The initiator/ sender is behind NAT. On the Capture the control session setup receives the private IP Address.

 

But now tested with twping from behind the same NAT, used “-Z” option, the private IP address does not flow into the control session (goes 0.0.0.0) but again no answer comes back.

 

From the capture done on the target machine, twamp-server, no traffic ever goes out. (Aside greeting control session tear up/ down).

 

From: Mark Feit <>
Sent: Monday, August 9, 2021 7:25 PM
To: Daniel Bernardo <>;
Subject: Re: TWAMP Server - Responder

 

Daniel Bernardo writes:

 

Using Accedian solutions as client, TWAMP Control negotiates the testing port, Controller starts sending traffic to this port, reaches the server, and then nothing happens. No reply.  How to troubleshoot this ?

 

I’d start on the server where twampd is running and make sure “twping localhost” works.  If it does, install the twamp-client package on the server running Accedian and make sure that works as expected.  There’s always the possibility that return test traffic is being blocked somewhere.  I have no idea what Accedian is using for its TWAMP implementation and can’t help debug that. 

 

Aug  6 17:01:51 experience01 twampd[31608]: FILE=time.c, LINE=118, NTP: STA_NANO should be set. Make sure ntpd is running, and your NTP configuration is good.

 

NTP is running but from chrony.

 

That shouldn’t be a problem; the twampd code looks for something NTP-specific and complains if it isn’t present.  That’s a holdover from the pre-Chrony days but shouldn’t any effects on the measurements.

 

--Mark