I once had similar problems which turned out to be due to TCP ECN being
enabled. Use tcpdump/tethereal to look at what's going on.
There seem to be some thoughts as to akamai being the possible culprit,
specifically as it interacts with Linux. I'm hoping a few of you Linux
users out there will give it a shot, telnetting to port 80 on these IPs
several times to see if you can get a failure. Any thoughts on this issue
are greatly appreciated.