netcat小工具使用

接收端:nc -l 1789 > test1.txt

發送端:nc 1.1.1.1 1789 < test1.txt

使用nc傳檔案要比scp快不少，當然，安全性低了.

[[email protected]]# nc -h

usage: nc [-46DdhklnrStUuvzC] [-i interval] [-p source_port]

 [-s source_ip_address] [-T ToS] [-w timeout] [-X proxy_version]

 [-x proxy_address[:port]] [hostname] [port[s]]

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 port Specify local port for remote connects

-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]

用來測試upd端口是否正常 a端：nc -ul 161 b端: nc -u a.a.a.a 161 在b端随便輸入字元，看是否能夠傳到a端。 

1.掃描TCP端口.

[[email protected] ~]# nc -v -z -w2 172.20.9.30 3388-3390

nc: connect to 172.20.9.30 port 3388 (tcp) failed: Connection refused

Connection to 172.20.9.30 3389 port [tcp/ms-wbt-server] succeeded!

nc: connect to 172.20.9.30 port 3390 (tcp) failed: Connection refused

2.掃描UDP端口.

[[email protected] ~]# nc -u -v -z -w2 172.20.5.5 160-163

Connection to 172.20.5.5 161 port [udp/snmp] succeeded!

Connection to 172.20.5.5 162 port [udp/snmptrap] succeeded!