in.rlogind(1M) System Administration Commands in.rlogind(1M)
NAME
in.rlogind, rlogind - remote login server
SYNOPSIS
/usr/sbin/in.rlogind [-k5eExXciPp] [-s tos] [-S keytab] [-M realm]
DESCRIPTION
in.rlogind is the server for the rlogin(1) program. The server provides a remote login facility with authentication based on Kereros V5 or
privileged port numbers.
in.rlogind is invoked by inetd(1M) when a remote login connection is established. When Kerberos V5 authentication is required (see option
-k below), the authentication sequence is as follows:
o Check Kerberos V5 authentication.
o Check authorization according to the rules in krb5_auth_rules(5).
o Prompt for a password if any checks fail and /etc/pam.conf is configured to do so.
If Kerberos V5 authentication is not enabled, then the authentication procedure follows the standard rlogin protocol:
o The server checks the client's source port. If the port is not in the range 512-1023, the server aborts the connection.
o The server checks the client's source address. If an entry for the client exists in both /etc/hosts and /etc/hosts.equiv, a user log-
ging in from the client is not prompted for a password. If the address is associated with a host for which no corresponding entry
exists in /etc/hosts, the user is prompted for a password, regardless of whether or not an entry for the client is present in
/etc/hosts.equiv. See hosts(4) and hosts.equiv(4).
Once the source port and address have been checked, in.rlogind allocates a pseudo-terminal and manipulates file descriptors so that the
slave half of the pseudo-terminal becomes the stdin, stdout, and stderr for a login process. The login process is an instance of the
login(1) program, invoked with the -r.
The login process then proceeds with the pam(3PAM) authentication process. See SECURITY below. If automatic authentication fails, it
reprompts the user to login.
The parent of the login process manipulates the master side of the pseudo-terminal, operating as an intermediary between the login process
and the client instance of the rlogin program. In normal operation, a packet protocol is invoked to provide <Ctrl-S> and <Ctrl-Q> type
facilities and propagate interrupt signals to the remote programs. The login process propagates the client terminal's baud rate and termi-
nal type, as found in the environment variable, TERM. See environ(4).
OPTIONS
The following options are supported:
-5 Same as -k, for backwards compatibility.
-c Requires Kerberos V5 clients to present a cryptographic checksum of initial connection information like the name of the
user that the client is trying to access in the initial authenticator. This checksum provides additionl security by pre-
venting an attacker from changing the initial connection information. This option is mutually exclusive with the -i option.
-e Creates an encrypted session.
-E Same as -e, for backwards compatibility.
-i Ignores authenticator checksums if provided. This option ignores authenticator checksums presented by current Kerberos
clients to protect initial connection information. Option -i is the opposite of option -c.
-k Allows Kerberos V5 authentication with the .k5login access control file to be trusted. If this authentication system is
used by the client and the authorization check is passed, then the user is allowed to log in.
-M realm Uses the indicated Kerberos V5 realm. By default, the daemon will determine its realm from the settings in the krb5.conf(4)
file.
-p Prompts for authentication only if other authentication checks fail.
-P Prompts for a password in addition to other authentication methods.
-s tos Sets the IP TOS option.
-S keytab Sets the KRB5 keytab file to use. The/etc/krb5/krb5.keytab file is used by default.
-x Same as -e, for backwards compatibility.
-X Same as -e, for backwards compatibility.
USAGE
rlogind and in.rlogind are IPv6-enabled. See ip6(7P). IPv6 is not currently supported with Kerberos V5 authentication.
Typically, Kerberized rlogin service runs on port 543 (klogin) and Kerberized, encrypted rlogin service runs on port 2105 (eklogin). The
corresponding FMRI entries are:
svc:/network/login:klogin (rlogin with kerberos)
svc:/network/login:eklogin (rlogin with kerberos and encryption)
SECURITY
in.rlogind uses pam(3PAM) for authentication, account management, and session management. The PAM configuration policy, listed through
/etc/pam.conf, specifies the modules to be used for in.rlogind. Here is a partial pam.conf file with entries for the rlogin command using
the "rhosts" and UNIX authentication modules, and the UNIX account, session management, and password management modules.
rlogin auth sufficient pam_rhosts_auth.so.1
rlogin auth requisite pam_authtok_get.so.1
rlogin auth required pam_dhkeys.so.1
rlogin auth required pam_unix_auth.so.1
rlogin account required pam_unix_roles.so.1
rlogin account required pam_unix_projects.so.1
rlogin account required pam_unix_account.so.1
rlogin session required pam_unix_session.so.1
With this configuration, the server checks the client's source address. If an entry for the client exists in both /etc/hosts and
/etc/hosts.equiv, a user logging in from the client is not prompted for a password. If the address is associated with a host for which no
corresponding entry exists in /etc/hosts, the user is prompted for a password, regardless of whether or not an entry for the client is
present in /etc/hosts.equiv. See hosts(4) and hosts.equiv(4).
When running a Kerberized rlogin service (with or without the encryption option), the pam service name that should be used is "krlogin".
If there are no entries for the rlogin service, then the entries for the "other" service will be used. If multiple authentication modules
are listed, then the user may be prompted for multiple passwords. Removing the "pam_rhosts_auth.so.1" entry will disable the
/etc/hosts.equiv and ~/.rhosts authentication protocol and the user would always be forced to type the password. The sufficient flag indi-
cates that authentication through the pam_rhosts_auth.so.1 module is "sufficient" to authenticate the user. Only if this authentication
fails is the next authentication module used.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|Availability |SUNWrcmds |
+-----------------------------+-----------------------------+
SEE ALSO
login(1), svcs(1), rlogin(1), in.rshd(1M), inetadm(1M), inetd(1M), svcadm(1M), pam(3PAM), environ(4), hosts(4), hosts.equiv(4),
krb5.conf(4), pam.conf(4), attributes(5), krb5_auth_rules(5), pam_authtok_check(5), pam_authtok_get(5), pam_authtok_store(5),
pam_dhkeys(5), pam_passwd_auth(5), pam_unix_account(5), pam_unix_auth(5), pam_unix_session(5), smf(5)
DIAGNOSTICS
All diagnostic messages are returned on the connection associated with the stderr, after which any network connections are closed. An error
is indicated by a leading byte with a value of 1.
Hostname for your address unknown. No entry in the host name database existed for the client's machine.
Try again. A fork by the server failed.
/usr/bin/sh: ... The user's login shell could not be started.
NOTES
The authentication procedure used here assumes the integrity of each client machine and the connecting medium. This is insecure, but it is
useful in an ``open'' environment.
A facility to allow all data exchanges to be encrypted should be present.
The pam_unix(5) module is no longer supported. Similar functionality is provided by pam_authtok_check(5), pam_authtok_get(5), pam_auth-
tok_store(5), pam_dhkeys(5), pam_passwd_auth(5), pam_unix_account(5), pam_unix_auth(5), and pam_unix_session(5).
The in.rlogind service is managed by the service management facility, smf(5), under the service identifier:
svc:/network/login:rlogin (rlogin)
svc:/network/login:klogin (rlogin with kerberos)
svc:/network/login:eklogin (rlogin with kerberos and encryption)
Administrative actions on this service, such as enabling, disabling, or requesting restart, can be performed using svcadm(1M). Responsibil-
ity for initiating and restarting this service is delegated to inetd(1M). Use inetadm(1M) to make configuration changes and to view config-
uration information for this service. The service's status can be queried using the svcs(1) command.
SunOS 5.10 4 Aug 2004 in.rlogind(1M)