Your client is not an HTTP client. It completely ignores the Content-Length header which tells the length of the response body. That is the mechanism HTTP uses to indicate when the response ends. Instead, it reads the response by lines which fails as you discovered when the response does not end with a LF. The solution is to read the response header by line, parse out the Content-Length, and then read the body by blocks.

Also, your client should not advertise HTTP 1.1 if it does not support it. Real HTTP will assume they can use stuff like chunked encoding and your client won't handle it.

Finally, is there a reason you can't use LWP for the HTTP client? Or HTTP::Daemon for the server? Both of them handle all the nasty details of the HTTP protocol.