netcat

A featured networking utility which reads and writes data across network connections, using the TCP/IP protocol.

https://netcat.sourceforge.net

Examples

Send HTTP request

The request was fetched with tcpdump.

   1 cat request1.txt | nc 192.168.1.1 8080

Send SMTP request

The request was fetched with tcpdump.

ehlo example.com
mail from: userx@example.com
rcpt to: usery@example.net
quit

   1 cat requestsmtp1.txt | nc 192.168.1.1 25

Send hex string

http://unix.stackexchange.com/questions/82561/convert-a-hex-string-to-binary-and-send-with-netcat

• echo '0006303030304e43' | xxd -r -p | nc -l localhost 8181