ssh

SSH stands for "secure shell." It's a cryptographic networking protocol used for operating network services over an unsecured network.

Troubleshooting Bad Character Input In Host

Running the command stty -a in the remote host will find what character codes are to be expected by the server from the given keying client. Pressing Ctrl v then pressing your given key will write the character codes recieved by the server.

If your character codes are the same as the codes displayed using stty -a, the way to restore key functionality is ti produce your client's terminal's terminfo file using infocmp > terminfo. Copy terminfo to the server using scp, then from the server run tic terminfo in order to install your terminal's terminfo to the server. After a restart, the error should be gone.

Sources

1. Secure Shell Wikipedia Page
2. Serverfault Message Board Discussion