TCP Knocking provides a port knocking implementation that attempts to solve problems of opening firewalls to provide remote access by incorporating the knock into unused fields in the TCP handshake sequence packets, rather than using UDP packets with secret ports.
You can download it from the following link: https://packetstormsecurity.com/files/download/52773/tcpknock-v01.tar.bz
Source: https://packetstormsecurity.com/files/52773/tcpknock-v01.tar.bz.html