Rlogin, RSH, and RCP

The CompTIA Network tests you on rlogin, RSH, and RCP. These are three oldschool programs in the UNIX world. The R stands for remote and, like Telnet and SSH, these programs provide remote access and control of servers. Also like Telnet, they do not encrypt data and thus, should not be used across the Internet. Here is a quick breakdown of the suite:

• Rlogin Remote login works very similarly to Telnet. You simply run the program with the host name of the server and you can connect and run commands just like with Telnet. It has one very nice advantage over Telnet in that it can be configured to log in automatically without the need to enter a user name and password. Rlogin works over TCP port 513.
• RSH Remote Shell allows you to send single commands to the remote server. Whereas rlogin is designed to be used interactively, RSH can be easily integrated into a script. RSH runs over TCP port 514 by default.
• RCP Remote Copy provides the capability to copy files to and from the remote server without the need to resort to FTP or NFS (Network File System, the UNIX form of folder sharing). RCP can also be used in scripts and shares TCP port 514 with RSH.