perfSONAR User Q&A and Other Discussion

[Daniel Bernardo <>]

Thank you for the update Mark,

 

Two notes:

 

Tested with Accedian Solution whiteout NAT and worked flawlessly,

Is there a TWAMP “Light Reflector” tool/ package on perfSONAR ?

 

Thank you,

 

 

From: Mark Feit <>
Sent: Tuesday, August 10, 2021 5:37 PM
To: Daniel Bernardo <>;
Subject: Re: TWAMP Server - Responder

 

Daniel Bernardo writes:

 

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.

 

The -Z switch should work with NAT if that’s what it really is.  Most of what’s billed as NAT is actually port/address translation (PAT); our usual stance is that we don’t support PAT because of the wide variety of implementations that behave in different ways.

 

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

 

I did a quick test on one of my systems by attaching strace to the server and found that it received packets but doesn’t appear to send them, even wrong ones.  We have an issue open on a similar problem to that one, and I’ve appended a comment about it:  https://github.com/perfsonar/owamp/issues/65.

 

--Mark