R-services run on port 512,513,514.
From a Unix-based platform, you use rsh, rlogin, and rexec clients to access the respective r-services running on a remote host.
The problem with r services is that it allows remotely logging to the server without requiring any authentication.
rlogin -l root 192.168.145.133
Make sure rsh-client is installed.Else it will default to ssh and hence will prompt for ssh key.
Alternate way to exploit:
rsh 192.168.145.133