Can curl make a connection to any TCP ports, not just HTTP/HTTPS?

May 6, 2023 by Tarik

Yes, it’s possible, the syntax is curl [protocol://]<host>[:port], for example:

curl example.com:1234

If you’re using Bash, you can also use pseudo-device /dev files to open a TCP connection, e.g.:

exec 5<>/dev/tcp/127.0.0.1/1234
echo "send some stuff" >&5
cat <&5 # Receive some stuff.

^{See also: More on Using Bash’s Built-in /dev/tcp File (TCP/IP).}