Re: [Discuss-gnuradio] UHD: cannot find usrp2.

[Josh Blum]

On 12/17/2010 06:16 PM, Marcus D. Leech wrote:
> On 12/17/2010 06:00 PM, Josh Blum wrote:
>> firewall perhaps? try this:
>>
>> http://www.ettus.com/uhd_docs/manual/html/usrp2.html#debugging-networking-problems
>>
>>
> I've found that on recent Fedoren, uhd_find_devices doesn't work, but if
> I explicitly:
> 
> uhd_usrp_probe --args "addr=192.168.10.2"
> 
> It works just fine.
> 
> I haven't tracked down the exact firewall rules that cause this to
> happen yet.
> 
> Josh: how does uhd_find_devices do its thing?  Does it send out a UDP
> broadcast, and if so, how does the USRP2 respond?
>   This will help me figure out what particular firewall rule is getting
> in the way.
> 
> 

Ok from the docs:

http://www.ettus.com/uhd_docs/manual/html/usrp2.html#debugging-networking-problems

Disable the firewall: If uhd_find_devices gives you nothing but
uhd_find_devices --args addr=192.168.10.2 yeilds a discovered device,
then your firewall may be blocking replies to UDP broadcast packets.

If you dont specify an address. UHD sends a broadcast on each interface.
>From when I last tested, i think the usrp2 did indeed get the packet and
send the reply, which means that the firewall blocked the response. This
can also be confirmed with wireshark.

Disabling the firewall entirely seems to fix it. Thats using a
sledgehammer when you need a chisel. :-)

-josh