blastboot:
Why did you choose 64 bytes?? What is the maximum bytes per packet that ethernet shield can send??
The maximum is about 1400. However, you can't use a variable declaration like this.
byte outBuf[1400];
You don't have that much memory in an Uno. So I wanted to insure it might be able to run on an Uno, but also send more data than header. The header is normally 48 bytes, so I picked 64.