In the *shell* buffer:
M-x rename-buffer RET *shell-1* RET M-x shell RET
This will then start a second shell. The key is that no buffer named *shell* can exist. It might be preferable to use M-x rename-uniquely to rename the *shell* buffer instead of M-x rename-buffer.
Use M-x rsh or M-x telnet to open remote sessions rather than doing rsh or telnet within the local shell buffer.