How to detect if network is dropping UDP packets?

I'm got a video streaming application that runs fine in my office but fails miserably at the customer location. The symptom is that every couple of seconds, I stop receiving UDP packets for 2 seconds, then the stream resumes as if nothing is wrong.

I ran http://www.pingtest.net/ at the customer location and it came back excellent. No dropped packets and low latency. The only difference I noticed between our two locations is that ping google.ca times-out at their location but works in mine.

How do I test whether the network I am on blocks incoming UDP packets? Is there a way for me to isolate who is dropping the packets?

Solution 1:

You can try to establish a UDP connection with netcat.

On a machine A outside the consumer's network run:

nc -u -l -p 1234            # if using netcat-traditional
nc -u -l 1234               # if using netcat-openbsd (as pointed out by @JamesHaigh)

Note the -u which instructs netcat to use UDP. (And also be aware, that there are different versions of netcat, which will need the -p parameter or not; given are the variants for the two most common(?) ones, both included in Debian.)

On consumer location: nc -u [addr of machine A] 1234.

Try to send send some text, or even better use pipes to send a file between both locations and do a diff afterwards.

Solution 2:

at server side, establish a UPD server with

iperf -s -u

at client side, check UDP connection with

iperf -u -c <IP Address of Server>

Solution 3:

On serverside use

iperf -u -p <port> -s

On client side use

iperf -u -p <port> -c <domain or ip>

Make sure port allowed on firewall. This will give u a report like this after test

[ ID] Interval       Transfer     Bandwidth        Jitter   Lost/Total Datagrams

[  1]  0.0-10.0 sec  1.25 MBytes  1.05 Mbits/sec   3.722 ms    1/  893 (0.11%)