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1.7. Managing Data Using the ncat utility
IPv4 and IPv6, open connections, send packets, perform port scanning, and supports higher-level features such as SSL, and connection broker.
nc command can also be entered as ncat, using the identical options. For more information about the ncat options, see the New networking utility (ncat) section in the Migration Planning Guide and the ncat(1) man page.
Installing ncat
root:
yum install ncat
~]# yum install ncat
Brief Selection of ncat Use Cases
Example 1.1. Enabling Communication between a Client and a Server
- Set a client machine to listen for connections on TCP port 8080:
ncat -l 8080
~]$ ncat -l 8080Copy to Clipboard Copied! Toggle word wrap Toggle overflow - On a server machine, specify the IP address of the client and use the same port number:
ncat 10.0.11.60 8080
~]$ ncat 10.0.11.60 8080Copy to Clipboard Copied! Toggle word wrap Toggle overflow You can send messages on either side of the connection and they appear on both local and remote machines. - Press
Ctrl+Dto close the TCP connection.
Note
nc commands with the –u option. For example:
ncat -u -l 8080
~]$ ncat -u -l 8080
Example 1.2. Sending Files
- On a client machine, to listen a specific port transferring a file to the server machine:
ncat -l 8080 > outputfile
~]$ ncat -l 8080 > outputfileCopy to Clipboard Copied! Toggle word wrap Toggle overflow - On a server machine, specify the IP address of the client, the port and the file which is to be transferred:
ncat -l 10.0.11.60 8080 < inputfile
~]$ ncat -l 10.0.11.60 8080 < inputfileCopy to Clipboard Copied! Toggle word wrap Toggle overflow
Note
ncat -l 8080 < inputfile
~]$ ncat -l 8080 < inputfile
ncat -l 10.0.11.60 8080 > outputfile
~]$ ncat -l 10.0.11.60 8080 > outputfile
Example 1.3. Creating an HTTP proxy server
ncat -l --proxy-type http localhost 8080
~]$ ncat -l --proxy-type http localhost 8080
Example 1.4. Port Scanning
–z option and specify a range of ports to scan:
ncat -z 10.0.11.60 80-90
~]$ ncat -z 10.0.11.60 80-90
Connection to 192.168.0.1 80 port [tcp/http] succeeded!
Example 1.5. Setting up Secure Client-Server Communication Using SSL
SSL on a server:
ncat -e /bin/bash -k -l 8080 --ssl
~]$ ncat -e /bin/bash -k -l 8080 --ssl
ncat --ssl 10.0.11.60 8080
~]$ ncat --ssl 10.0.11.60 8080
Note
SSL connection, the server requires the --ssl-cert and --ssl-key options, and the client requires the --ssl-verify and --ssl-trustfile options. For information on OpenSSL, see the Using OpenSSL section in the Security Guide.