1G eth UDP / IP Stack

I could not get it implemented on ML605. I used your xv6mac_straight.vhd module. When I am running the java app, I am not getting any response back. In Wireshark, I could see that ML605 is responding to ARP request, but it is not responding to UDP packets. Any idea, what am I missing? Also, last entry in the ucf file "*mac_bloack/gtx_clk_bufg" error out during mapping. So, I commented out that line. Is it okay? Any help from you is greatly appreciated.

Thank you.

I could get it worked on ML605 with Xilinx mac block. But, with xv6mac_straight.vhd, it did not work. The last entry in UCF file error out. But, I will close this request since it worked with xilinx mac block. Thanks Peter for your help.