On 06/26/2014 12:36 PM, CLOSE Dave issued this missive:
Rick Stevens wrote:
Quite odd. Seems to work on my machine. In one window, I did a
nc -lu 29531
and in another:
echo 'Hello there!' | nc -u localhost 29531
and the first window saw the message. Try the same and see if it works.
Yes, that works for me. Further, this works when run from a different machine on the same network:
echo "UDP broadcast" \ | socat - UDP4-DATAGRAM:255.255.255.255:29531,so-broadcast
Examining the packets as they are captured by tcpdump, both the ones NC sees and the ones it doesn't, I don't find anything unusual. No checksum or length errors, for example. And comparing them to the one generated by socat doesn't reveal any obvious significant difference, either.
Uhm, gee. Since another host on the same network gets through, the one sending packets that NC doesn't get must have something set in the TCP stack that nc doesn't like. I'd check the flags on the packets that nc doesn't see. It might be really subtle. ---------------------------------------------------------------------- - Rick Stevens, Systems Engineer, AllDigital ricks@alldigital.com - - AIM/Skype: therps2 ICQ: 22643734 Yahoo: origrps2 - - - - Try to look unimportant. The bad guys may be low on ammo. - ----------------------------------------------------------------------