TCP/IP problem with Windows 7 (IP Header is 24 bytes)

[sarodrig]

My board works just fine with Windows XP. However, when I connect it to a Windows 7 machine, the IP header is increased by 4 bytes ("Options" bytes at the very end of the field, just before the TCP/IP header starts). While the length byte in the IP header appears to account for this, the data field still ends up off by 4 bytes. In other words, my TCPGet function starts returning values on the 4 bytes before my data starts, and the last 4 bytes are cut off.

I assume this is a bug in the TCP/IP stack. I'm using CCS' version of the Microchip v3.75 stack on a PIC18F67J60. We've worked around this for now by just padding our data field with 4 bytes at the end, but this is a band-aid solution.

Has anyone else had this problem? Is there an easy fix?