This module version has a number of limitations.
The 'root' privilege is required to use it.
The reason for this limitation is not documented
but looks like it's inherent to rcmd (see rcmd(3) man page).
Error handling is flawed (croak() expects a 'string' value).
The ECONNREFUSED errno ('Connection refused') is not handled in the port scan. This return code is possible if the 'backlog' parameter is reached on the peer socket used by rshd (see listen(2) man page).
The test case is limited to 'use Net::Rsh'.
The test case for the method new(), at least, could be added.
The test case for the method rsh() would be helpful, but configuration issues make this tricky.
Useful module - Used succesfully with 'root' privileges.