This program is
not for user execution. The usage message indicates this.
Kerberos Version 4
rsh did not support encryption. In order to perform
encrypted file transfer, the version 4
rcp program did a second authentication, directly to the
rcp process at the other end. This meant that
rcp needed to be
setuid to root in order to read the
krb-srvtab file on the remote end.
Rather than add this complexity into the main Kerberos 5
rcp the Kerberos 5
kshd instead detects the use of Kerberos 4 authentication, and checks the
command for the program name
rcp and then substitutes the full pathname of
v4rcp instead. Since
v4rcp is installed
setuid to root, it can perform the the authentication and get the session key
needed to encrypt the file transfer.
Kerberos 5
rcp instead uses the encryption support built in to Kerberos 5
rsh and
kshd directly.
