|RFC2616 says that servers should use CRLF as the end of line terminator for headers, but it's recommended that clients accept just a LF.|
I ran into a problem with running Perlbal in front of Arc. Perlbal worked fine for most of my pages, but it got confused when I was delivering a static file that contained CR's.
I surmise that perhaps perlbal is heuristically looking at the first block of characters in the response looking for a CR; if it sees one my suspicion is that it then expects the headers line to be terminated with CRLF.
In any case when I changed srv to pedantically output CRLF for the response headers then perlbal was able to forward all of my pages.