Technical data

16
Remote (R) Commands
The TCP/IP Services software includes client and server implementations of the
Berkeley Remote (R) command applications: RCP, RLOGIN, RSH, REXEC, and
RMT/RCD. These applications provide end users with the following capabilities:
RCP Allows files to be copied between remote hosts.
RLOGIN Provides interactive access to remote hosts.
RSH Passes a command to a remote host for execution.
REXEC Authenticates and executes RCP and other commands.
RMT/RCD Provides remote access to magnetic tape and CD-ROM drives.
This chapter reviews key concepts and describes:
• How to manage the R command servers (Section 16.2)
• Security considerations (Section 16.3)
• How to create a welcome message (Section 16.4)
• How the Remote Magnetic Tape/Remote CD-ROM (RMT/RCD) service
operates (Section 16.5)
For information about using these applications, see the DIGITAL TCP/IP
Services for OpenVMS User’s Guide.
16.1 Key Concepts
In addition to password authentication, the R commands use a system based on
trusted hosts and users. Trusted users on trusted hosts are allowed to access
the local system without providing a password. Trusted hosts are also called
‘‘equivalent hosts’’ because the software assumes that users given access to a
remote host should be given equivalent access to the local host. The system
assumes that user accounts with the same name on both hosts are ‘‘owned’’ by
the same user. For example, the user logged in as
molly on a trusted system is
granted the same access as a user logged in as molly on the local system.
This authentication system requires databases that define the trusted hosts and
the trusted users. On UNIX systems, these databases are:
• /etc/hosts.equiv
This file defines the trusted hosts and users for the entire system.
• .rhosts
This file defines the trusted hosts and users for an individual user account.
This file is located in the user’s home directory.
On OpenVMS hosts, the proxy database TCPIP$PROXY.DAT defines trusted
hosts and users for the entire system.
Remote (R) Commands 16–1