Udp.sendPacket not working?

I've recently got myself an ethernet shield (DFRobot DFR0006) and am using it with a DFRobot Duemilanove. It appears to be working fine until I start using Udp.sendPacket. I'm using 0022 of the arduino software and using the UDPSendReceiveString example. I can happily send a UDP string to the arduino, but the response never comes.

I've tried using a Mac to be the sender, and also Linux. Both do the same, which is sit waiting for a response. The lights on the ethernet shield flash to show they're transmitting, but the correct response never comes.

Below is a tcpdump from the Linux box:

11:50:33.283739 IP > UDP, length 5 = PC sending UDP packet to Arduino
11:50:34.361768 arp who-has tell
11:50:34.563974 arp who-has tell
11:50:34.766207 arp who-has tell
11:50:34.968440 arp who-has tell
11:50:35.170673 arp who-has tell
11:50:35.372906 arp who-has tell
11:50:35.575144 arp who-has tell
11:50:35.777373 arp who-has tell
11:50:35.979606 arp who-has tell

So the ethernet shield appears to be sending back, but arp who-has / tell packets?

Am I doing something wrong (I've not changed the code at all, apart from the IP address which surely shouldn't have this type of effect), or do you think the ethernet shield is faulty?


maybe you have a mac address conflict?

Heh, my tcpdump was altered by myself to hide some public addresses :slight_smile: I was actually going between two subnets which required me to set the subnet mask and gateway addresses within the Ethernet.begin command.

So I'm now getting UDP responses, which means the hardware must be ok. Interesting effect though if you don't have the subnet mask or gateway address in for cross subnet talk :slight_smile:

Now to get the client on my PC working right now...