Hi Amos, On Tue, 13 Apr 2010, Amos Jeffries wrote: > Squid is following RFC 2616 requirements. When HTTP/1.1 request > containing "Expect: 100-continue" is going to pass through a > HTTP/1.0 proxy or server which can't handle the "100" status > messages a "417" message MUST be sent back instead. > > The expected result is that the client software will retry > immediately without the "Expect: 100-continue" conditions. Failing > that it's probably broken software. I see, thanks. I've been trying to track down why I can't get the flash player video to play. While this failure is mixed in there, I think this may be a red herring for the problem I'm experiencing. Others going through the same proxy have had success. Thanks again for your help, Gavin