[mistwang]

Thank you for your bug report.

The "Proxy" external application mode does not seem to work, unless the buffering option is set to "Yes"

What is the symptom when buffering option is set to "no"? No output? Still buffer output? Currupted output? Can you please send us some debug log?
[UPDATE] this bug has been identified and fixed.

The "Proxy" mode does not exhibit Apache-style tolerance of responses from HTTP servers that do not have a valid header (in this case, no header at all). Also, the operation never seemed to time out in this case with an error page, leaving the client browser spinning endlessly.

When you said "no header at all", do you mean that there is only a leading empty line to indicate the end of response header? or only the response status line followed by the empty line? I think Apache should add necessory header to the response to make it comply with HTTP protocol. Would you mind capturing an example response with "lynx -mime_header" and post it here?

Thank you very much!