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rhosts(4) [osf1 man page]

rhosts(4)						     Kernel Interfaces Manual							 rhosts(4)

rhosts, .rhosts - Specifies remote users that can use a local user account SYNOPSIS
The .rhosts file contains a list of remote users who are not required to supply a login password when they execute the rcp, rlogin, and rsh commands using a local user account. The .rhosts file is a hidden file in your home directory. It must be owned by you or the root user and it must not be writable by group or world, otherwise, it is not used. Moreover, although it is not required, it is sensible to set the permissions of the file to 600, so the file is not readable by group or world. Each entry in the file is of the following form: host [user] where: The name of the remote host. If the remote host is in a different domain than the local host, the full domain name must be speci- fied. The login name of the remote user. This field is optional. If this field is not specified, any user on the specified remote host is exempt from providing a password, and is assumed to have the same username on both the local and remote hosts. Optionally, an NIS netgroup name can be specified for the host name, user name, or both. Entries in the .rhosts file are either positive or negative. Positive entries allow access; negative entries deny access. The following entries are positive: hostname username +@netgroup In addition, the plus sign (+) can be used in place of the hostname or username. In place of the hostname, it means any remote host. In place of the username, it means any user. The following entries are negative: -hostname -username -@netgroup EXAMPLES
The following sample entries in the /u/chen/.rhosts file on host zeus allow users moshe and pierre at remote host venus and user robert at the hosts specified in the NIS netgroup chicago to log in to user chen's home directory on host zeus: venus moshe venus pierre +@chicago robert FILES
Specifies remote users who can use a local user account. RELATED INFORMATION
Commands: rcp(1), rlogin(1), rsh(1). Functions: ruserok(3). Files: hosts.equiv(4), netgroup(4). Functions: rcmd(3). delim off rhosts(4)

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HOSTS.EQUIV(5)						      BSD File Formats Manual						    HOSTS.EQUIV(5)

hosts.equiv, .rhosts -- trusted remote hosts and host-user pairs DESCRIPTION
The hosts.equiv and .rhosts files list hosts and users which are ``trusted'' by the local host when a connection is made via rlogind(8), rshd(8), or any other server that uses ruserok(3). This mechanism bypasses password checks, and is required for access via rsh(1). Each line of these files has the format: hostname [username] The hostname may be specified as a host name (typically a fully qualified host name in a DNS environment) or address, +@netgroup (from which only the host names are checked), or a ``+'' wildcard (allow all hosts). The username, if specified, may be given as a user name on the remote host, +@netgroup (from which only the user names are checked), or a ``+'' wildcard (allow all remote users). If a username is specified, only that user from the specified host may login to the local machine. If a username is not specified, any user may login with the same user name. EXAMPLES
somehost A common usage: users on somehost may login to the local host as the same user name. somehost username The user username on somehost may login to the local host. If specified in /etc/hosts.equiv, the user may login with only the same user name. +@anetgroup username The user username may login to the local host from any machine listed in the netgroup anetgroup. + + + Two severe security hazards. In the first case, allows a user on any machine to login to the local host as the same user name. In the second case, allows any user on any machine to login to the local host (as any user, if in /etc/hosts.equiv). WARNINGS
The username checks provided by this mechanism are not secure, as the remote user name is received by the server unchecked for validity. Therefore this mechanism should only be used in an environment where all hosts are completely trusted. A numeric host address instead of a host name can help security considerations somewhat; the address is then used directly by iruserok(3). When a username (or netgroup, or +) is specified in /etc/hosts.equiv, that user (or group of users, or all users, respectively) may login to the local host as any local user. Usernames in /etc/hosts.equiv should therefore be used with extreme caution, or not at all. A .rhosts file must be owned by the user whose home directory it resides in, and must be writable only by that user. Logins as root only check root's .rhosts file; the /etc/hosts.equiv file is not checked for security. Access permitted through root's .rhosts file is typically only for rsh(1), as root must still login on the console for an interactive login such as rlogin(1). FILES
/etc/hosts.equiv Global trusted host-user pairs list ~/.rhosts Per-user trusted host-user pairs list SEE ALSO
rcp(1), rlogin(1), rsh(1), rcmd(3), ruserok(3), netgroup(5) HISTORY
The .rhosts file format appeared in 4.2BSD. BUGS
The ruserok(3) implementation currently skips negative entries (preceded with a ``-'' sign) and does not treat them as ``short-circuit'' neg- ative entries. BSD
November 26, 1997 BSD

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