Your mail to linux-kernel did not say which kernel you were running,
always a nice thing to know. The 2.1.x tcp code is sufficiently
different from 2.0.x that I don't want to fit the 2.0.30 patch to
2.1.29 right now. Can you run the tcpdump trace on both ends of the
link and mail me the results? Which kernel are the two ends running?