Tunnelshell is a client/server program written in C for Linux users that tunnels a shell using various methods which can bypass firewalls, such as fragmented packets, tcp ACK packets, UDP, ICMP, and raw IP packets (ipsec).
You can download it from the following link: https://packetstormsecurity.com/files/download/32231/tunnelshell_2.3.tgz
Source: https://packetstormsecurity.com/files/32231/tunnelshell_2.3.tgz.html

