NAME

hosts.equiv − list of trusted hosts (with NFS extensions)

DESCRIPTION

Hosts.equiv resides in directory /etc and contains a list of trusted hosts.  When an rlogin(1) or rsh(1) request from such a host is made, and the initiator of the request is in /etc/passwd, then no further validity checking is done. That is, rlogin does not prompt for a password, and rsh completes successfully.  So a remote user is “equivalenced” to a local user with the same user ID when the remote user is in hosts.equiv.

The format of hosts.equiv is a list of names, as in this example:

 host1
 host2
 +@group1
 -@group2

A line consisting of a simple host name means that anyone logging in from that host is trusted.  A line consisting of +@group means that all hosts in that network group are trusted.  A line consisting of −@group means that hosts in that group are not trusted.  Programs scan hosts.equiv linearly, and stop at the first hit (either positive for hostname and +@ entries, or negative for −@ entries).  A line consisting of a single + means that everyone is trusted. 

The .rhosts file has the same format as hosts.equiv. When user XXX executes rlogin or rsh, the .rhosts file from XXX’s home directory is conceptually concatenated onto the end of hosts.equiv for permission checking.  However, −@ entries are not sticky.  If a user is excluded by a minus entry from hosts.equiv but included in .rhosts, then that user is considered trusted. In the special case when the user is root, then only the /.rhosts file is checked. 

It is also possible to have two entries (separated by a single space) on a line of these files.  In this case, if the remote host is equivalenced by the first entry, then the user named by the second entry is allowed to log in as anyone, that is, specify any name to the −l flag (provided that name is in the /etc/passwd file, of course).  Thus

bullhead kim

allows kim to log in from bullhead as anyone.  The usual usage would be to put this entry in the .rhosts file in the home directory for nancy .  Then kim may log in as nancy when coming from bullhead. The second entry may be a netgroup, thus

 +@group1 +@group2

allows any user in group2 coming from a host in group1 to log in as anyone. 

FILES

/etc/hosts.equiv

SEE ALSO

rlogin(1), rsh(1), netgroup(5)

PRPQs 5799-WZQ/5799-PFF: IBM/4.3  —  Sept 1988