Ncat proxy server on Win7 rejects connections with HTTP/400

[nnposter]

When in proxy server mode on Win7, ncat immediately responds to a new connection with HTTP/1.0 400 Bad Request. This HTTP response happens before the client submits any data.

C:\>ncat -vvv -l --proxy-type http
Ncat: Version 7.70 ( https://nmap.org/ncat )
NCAT DEBUG: Initialized fdlist with 2 maxfds
Ncat: Listening on :::3128
NCAT DEBUG: Added fd 96 to list, nfds 1, maxfd 96
Ncat: Listening on 0.0.0.0:3128
NCAT DEBUG: Added fd 92 to list, nfds 2, maxfd 96
NCAT DEBUG: selecting, fdmax 96
NCAT DEBUG: select returned 1 fds ready
NCAT DEBUG: forking handler for 92
NCAT DEBUG: selecting, fdmax 96
NCAT DEBUG: Error reading Request-Line.

The same behavior is not observed on Linux.

[pkreuzt]

Same here with x64 Windows 10 v1809.