Level Goal
The password for the next level can be retrieved by submitting the password of the current level to port 30000 on localhost.

Commands you may need to solve this level: ssh, telnet, nc, openssl, s_client, nmap

Okay so i know how to use nc a bit, but lets see the manpage
man nc

The format should be nc hostname ports. So I tried.
nc localhost 30000 4wcYUJFw0k0XLShlDzztnTBHiqxU3b3e

but supplying the password wasn’t neccesarry it asks for it after making the connection, so i pasted it again and got the password of level 15 back.\

the password is BfMYroe26WYalil77FoDi9qh59eK5xNr