rhosts(5) File Formats Manual rhosts(5)Name
rhosts - list of hosts that are logically equivalent to the local host
The file allows a user who has an account on the local host to log in from a remote host without supplying a password. It also allows
remote copies to the local host.
If the file exists, it is located in a user's home directory. It is not a mandatory file, however.
The format of a file entry is:
The hostname is the name of the remote host from which the user wants to log into the local host. The username is the user's login name on
the remote host. If you do not specify a user name, the user must have the same login name on both the remote and local hosts.
The host names listed in the file may optionally contain the local BIND domain name. For more information on BIND, see the Guide to the
If a user is logged in to and wants to log in to a host called without supplying a password, she must:
o Have an account on
o Create a file in her home directory on
o Specify host1 ginger as an entry in the file.
If has the same login on both and she can simply specify host1 in her entry. You can allow the superuser of a remote system to log in
to your system without password protection or perform a remote copy by having a file in the root ( / ) directory, but it is not recom-
In addition to having a file, the superuser needs a terminal entry in the file for each pseudoterminal configured in the system. The
secure entry looks similar to the following:
ttyp3 none network secure
See the reference page for more information.
The following is a sample file for the user It is located in her home directory on She also has accounts on the hosts called and Her login
name on and is the same as on but her login on is
To enable to log in to from and without supplying a password, her on should contain the following entries:
See Alsohosts.equiv(5), ttys(5)
Introduction to Networking and Distributed System Services
Check Out this Related Man Page
hosts.equiv(4) Kernel Interfaces Manual hosts.equiv(4)NAME
hosts.equiv - A file containing the names of remote systems and users that can execute commands on the local system
The /etc/hosts.equiv file and the .rhosts file in a user's home directory contain the names of remote hosts and users that are equivalent
to the local host or user. An equivalent host or user is allowed to access a local nonsuperuser account with the rsh command or rcp com-
mand, or to log in to such an account without having to supply a password.
The /etc/hosts.equiv file specifies equivalence for an entire system, while a user's .rhosts file specifies equivalence between that user
and remote users. The local user and the target system exist in the same area as the hosts.equiv file. The .rhosts file must be owned by
the user in whose home directory the file is located, or by the superuser. It cannot be a symbolic link.
Each line, or entry, in hosts.equiv or .rhosts may consist of the following: A blank line. A comment (begins with a #). A host name (a
string of any printable characters except newline, #, or white space). In addition, an NIS netgroup can be specified in place of the host
name. A host name followed by white space and a user name. In addition, an NIS netgroup can be specified in place of the host name, user
name, or both. A single plus (+) character. This means any host and user. The keyword NO_PLUS. This keyword disallows the use of the plus
character (+) to match any host or user on a system-wide basis. By default, the line containing this keyword is a comment. Remove the com-
ment character to disallow the use of the plus character.
Entries in the hosts.equiv file are either positive or negative. Positive entries allow access; negative entries deny access. The following
entries are positive: host name user name +@netgroup
In addition, the plus sign (+) can be used in place of the host name or user name. In place of the host name, it means any remote host. In
place of the user name, it means any user.
The following entries are negative: -host name -user name -@netgroup
To be allowed access or denied access, a user's remote host name and user name must match an entry in hosts.equiv or .rhosts. The
hosts.equiv file is searched first; if a match is found, the search ends. Therefore, the order in which the positive and negative entries
appear is important. If a match is not found, .rhosts is searched if it exists in the user's home directory.
A host name or user name can match an entry in hosts.equiv in one of the following ways: The official host name (not an alias) of the
remote host matches a host name in hosts.equiv. The remote user name matches a user name in hosts.equiv. If a user name parameter is
included in the hosts.equiv file, this means that the remote user is a trusted user and is allowed to rlogin to any local user account
without being prompted for a password. Otherwise, if the user name parameter is not specified in the hosts.equiv file, the name of the
remote user must match that of the local user. If the remote user name does not match a user name in hosts.equiv, the remote user name
matches the local user name.
For security purposes, the files /etc/hosts.equiv and .rhosts should exist and be readable and writable only by the owner, even if they are
The following are sample entries in an /etc/hosts.equiv file: # Allows access to users on host1 and host2 that have accounts on this host:
host1 host2 # Allows access to user johnson on host1 to any local user: host1 johnson # Allows access to all users on systems specified in
netgroup chicago +@chicago # Denies access to users specified in netgroup finance on host5 host5 -@finance # Allows access to all users on
all systems except root + -root
Commands: rcp(1), rlogin(1), rsh(1)
Daemons: rlogind(8), rshd(8) delim off