UDP sender/receiver what the heck am I doing wrong

GNU Radio
1

Attached, you’ll find a pair of very-simple .grcs

One is a UDP sender (using a pair of UDP sinks)

The other is a UDP receiver (using a pair of UDP sources)

The sender clearly works, as verified by ‘tcpdump’ at the receiving
system. The ports are correct, etc.

But nothing is coming out of the UDP sources.

My MTU is 1500, so the UDP frame size of 1472 is correct.

And, I’ll repeat, ‘tcpdump’ sees the traffic.

2

I saw something similar last week.

3

On 07/14/2014 11:47 AM, John M. wrote:

I saw something similar last week.

Opened up firewall rules. That didn’t help. But netcat could see the
traffic, so it’s being delivered up to userland.

4

Also saw the same thing. =)

5

On 07/14/2014 12:00 PM, John M. wrote:

Also saw the same thing. =)

You can’t leave the bind-addr blank–set it to the interface addy over
which you expect packets to arrive, that works.

I suspect that there’s some missing code to deal properly with a
“promiscuous bind” in the UDP source block.

–
Marcus L.
Principal Investigator
Shirleys Bay Radio Astronomy Consortium

6

On 07/14/2014 12:36 PM, Mike J. wrote:

Set the bind address to ‘0.0.0.0’ to listen on all interfaces. This
would be a good default setting.

Yup, this works.

That was one of my test-cases before I changed the firewall rules…

7

Set the bind address to ‘0.0.0.0’ to listen on all interfaces. This
would
be a good default setting.

–
Mike J. M0MIK BSc MIET
Email: [email protected]
Web: http://scanoo.com