Common Linux Network Tools: netcat for batch host service Scanning

Common Linux Network Tools: netcat for batch host service Scanning

Netcat, also known as Swiss Army knife, is a common network tool used by hackers and system administrators. It was initially developed to transfer files and subsequently developed many powerful functions, such as batch host service scanning.

We have introduced another more common batch host service scanning tool: nmap.

Netcat installation is also very simple. Install netcat directly using yum:

Yum install nc

Generally, it is not recommended to install nc in the production environment. In addition to batch host service scanning, nc also supports port proxy and file transmission, which may cause security risks.

Netcat-Batch host service Scanning

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Common netcat parameters used during scanning:

-W: Set the timeout value.

-Z Input/Output Mode

-V: Display Command Execution Process

Common commands:

TCP protocol

Nc-v-z-w2 192.168.2.20.1-50

UDP protocol

Nc-v-z-w2-u 192.168.2.20.1-50

Netcat File Transfer

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Netcat can specify a local port number to enable the listening mode. The client can use the same netcat connection to enable the port sending information, which will be displayed on the server.

Enable listener

Nc-l 2389

Establish a connection

Nc localhost 2389

If you redirect the server output to a file, it can be used for file transfer:

Nc-l 2389> test

Transfer files

Cat testfile | nc localhost 2389

If the test is performed on a server, you can use & switch nc to the background task and run the client command.

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