NFSv2/usr/man/man5/hosts.equiv.5

.\" @(#)hosts.equiv.5 1.2 85/04/04 SMI; from UCB 4.2
.TH HOSTS.EQUIV 5 "1 February 1985"
.SH NAME
hosts.equiv \- list of trusted hosts
.SH DESCRIPTION
.IX  "hosts.equiv file"  ""  "\fLhosts.equiv\fP \(em trusted hosts list"
.IX  "trusted hosts list"  ""  "trusted hosts list \(em \fLhosts.equiv\fP"
.I Hosts.equiv
resides in directory
.I /etc
and contains a list of trusted hosts.
When an
.IR rlogin (1)
or
.IR rsh (1)
request from such a host is made, 
and the initiator of the request is in
.IR /etc/passwd ,
then no further validity checking is done.
That is,
.I rlogin
does not prompt for a password, and
.I rsh
completes successfully.
So a remote user is ``equivalenced'' to a local user
with the same user ID when the remote user is in
.IR hosts.equiv .
.PP
The format of
.I hosts.equiv
is a list of names, as in this example:
.IP
.ft L
 host1
 host2
 +@group1
 -@group2
.ft P
.PP
A line consisting of a simple host name
means that anyone logging in from that host is trusted.
A line consisting of
.I +@group
means that all members of that network group are trusted.
A line consisting of
.I \-@group
means that members of that group are not trusted.
Programs scan
.I 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.
.PP
The
.I .rhosts
file has the same format as
.IR hosts.equiv .
When user
.I XXX
executes
.I rlogin
or
.IR rsh ,
the
.I .rhosts
file from
.IR XXX 's
home directory is conceptually concatenated onto the end of
.I hosts.equiv
for permission checking.
However, \-@ entries are not sticky.
If a user is excluded by a minus entry from
.I hosts.equiv
but included in
.IR .rhosts ,
then that user is considered trusted.
In the special case when the user is root,
then only the
.I /.rhosts
file is checked.
.PP
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 user is equivalenced by the first entry,
then that user is allowed to log in as any member of the second entry.
Thus
.IP
.ft L
 sundown john
.ft P
.PP
allows anyone from sundown to log in as
.IR john ,
and
.IP
.ft L
 +@group1 +@group2
.ft P
.PP
allows any member of
.I netgroup1
to log in as a member of
.IR netgroup2 .
.SH FILES
/etc/hosts.equiv
.SH "SEE ALSO"
rlogin(1), rsh(1), netgroup(5)