usage: nc [-46DdhklnrStUuvzC] [-i interval] [-P proxy_username] [-p source_port] [-s source_ip_address] [-T ToS] [-w timeout] [-X proxy_protocol] [-x proxy_address[:port]] [hostname] [port] Command Summary: -4 Use IPv4 -6 Use IPv6 -D Enable the debug socket option -d Detach from stdin -h This help text -i secs Delay interval for lines sent, ports scanned -k Keep inbound sockets open for multiple connects -l Listen mode, for inbound connects -n Suppress name/port resolutions -P proxyuser Username for proxy authentication -p port Specify local port for remote connects -q secs quit after EOF on stdin and delay of secs (-1 to not quit) -r Randomize remote ports -S Enable the TCP MD5 signature option -s addr Local source address -T ToS Set IP Type of Service -C Send CRLF as line-ending -t Answer TELNET negotiation -U Use UNIX domain socket -u UDP mode -v Verbose -w secs Timeout for connects and final net reads -X proto Proxy protocol: "4", "5" (SOCKS) or "connect" -x addr[:port] Specify proxy address and port -z Zero-I/O mode [used for scanning] Port numbers can be individual or ranges: lo-hi [inclusive]