rsync-3.0.9 client does work with 0.92.3, but breaks with 0.93beta5 when forwarding to some squid-3.1.8.
Seems the difference is that 0.92.3 does set the "Proxy-Connection: keep-alive" for the server connection.
Attached are the output files of these commands:
$ strace -e trace=open,socket,connect,close,read,write,recv,send,select -o strace.0.92.3 -f -s 1024 cntlm -v > 0.92.3-v 2>&1
$ strace -e trace=open,socket,connect,close,read,write,recv,send,select -o strace.0.93beta5 -f -s 1024 cntlm -v > 0.93beta5-v 2>&1
The client was emulated with this command:
$ ( echo 'CONNECT 83.164.133.198:873 HTTP/1.0'; echo; sleep 5 ) | telnet <cntlmserver> <cntlmport>
Feels like this problem was introduced along http://sourceforge.net/tracker/?func=detail&aid=3512077&group_id=197861&atid=963162
0.93beta5: Output of cntlm -v
0.93beta5: strace output
0.92.3: Output of cntlm -v
0.92.3: strace output