If you have Squid and are having issues with your .NET application while uploading with errors like:
xxx.xx.xx.xxx TCP_MISS/417 2032 PUT http://temp-hudlvid.s3.amazonaws.com/... - NONE/- text/html
You might give this tweak a try:
In your squid.conf, add:
ignore_expect_100 on
Either that or hack your .NET client side config to do:
System.Net.ServicePointManager.Expect100Continue = False
It is probably better to break http 1.1 vs 1.0 compatibility with Squid than a Microsoft product though, as you know the GPL software will probably follow the spec better anyway.