rlogin(1)

NAME

rlogin — remote login

SYNOPSIS

rlogin rhost [-7] [-8] [-e e] [-l username]

rhost [-7] [-8] [-e e] [-l username]

In Kerberos V5 Network Authentication Environments

rlogin rhost [-7] [-8] [-e e] [-f|-F] [-k realm] [-l username] [-P]

rhost [-7] [-8] [-e e] [-f|-F] [-k realm] [-l username] [-P]

DESCRIPTION

The rlogin command connects your terminal on the local host to the remote host (rhost). rlogin acts as a virtual terminal to the remote system. The host name rhost can be either the official name or an alias as listed in the file /etc/hosts (see hosts(4)).

In non-secure or traditional environment, rlogin allows a user to log in on an equivalent remote host, rhost, bypassing the normal login/password sequence, in a manner similar to the remsh command (see remsh(1)). For more information about equivalent hosts and how to specify them in the files /etc/hosts.equiv and .rhosts, see hosts.equiv(4). The searching of the files /etc/hosts.equiv and .rhosts occurs on the remote host, and the .rhosts file must be owned by the remote user account.

If the originating user account is not equivalent to the remote user account, the originating user is prompted for the password of the remote account. If this fails, a login name and password are prompted for, as when login is used (see login(1)).

In a Kerberos V5 Network Authentication environment, rlogin uses the Kerberos V5 protocol to authenticate the connection to a remote host. If the authentication is successful, user authorization will be performed according to the command line options selected for rlogind (that is, -k, -K, -r, or -R). A password will not be required, so a password prompt will not be seen and a password will not be sent over the network where it can be observed. For further information on Kerberos authentication and authorization see the Secure Internet Services man page, sis(5) and rlogind(1M).

Although Kerberos authentication and authorization may apply, the Kerberos mechanism is not applied to the login session. All the information transferred between your host and the remote host is sent in cleartext over the network.

The terminal type specified by the current TERM environment variable is propagated across the network and used to set the initial value of your TERM environment variable on the remote host. Your terminal baud rate is also propagated to the remote host, and is required by some systems to set up the pseudo-terminal used by rlogind (see rlogind(1M)).

All echoing takes place at the remote site, so that (except for delays) the remote login is transparent.

If at any time rlogin is unable to read from or write to the socket connection on the remote host, the message Connection closed is printed on standard error and rlogin exits.

Options

rlogin recognizes the following options. Note that the options follow the rhost argument.

-7

Set the character size to seven bits. The eighth bit of each byte sent is set to zero (space parity).

-8

Use an eight-bit data path. This is the default HP-UX behavior.

To use eight-bit characters, the terminal must be configured to generate either eight-bit characters with no parity, or seven bit characters with space parity. The HP-UX implementation of rlogind (see rlogind(1M)) interprets seven bit characters with even, odd, or mark parity as eight-bit non-USASCII characters. You may also need to reconfigure the remote host appropriately (see stty(1) and tty(7)). Some remote hosts may not provide the necessary support for eight-bit characters. In this case, or if it is not possible to disable parity generation by the local terminal, use the -7 option.

-ee

Set the escape character to e. There is no space separating the option letter and the argument character. To start a line with the escape character, two of the escape characters must be entered. The default escape character is tilde (~). Some characters may conflict with your terminal configuration, such as ^S, ^Q, or backspace. Using one of these as the escape character may not be possible or may cause problems communicating with the remote host (see stty(1) and tty(7)).

-l username

This option can be used to set the user login name on the remote host to username. The default name is the current account name of the user invoking rlogin.

Kerberos-specific Options

The default Kerberos options for the applications are set in the krb5.conf configuration file. Refer to the appdefaults Section in the krb5.conf(4) manpage for more information. The options -f, and -F described in the subsequent paragraphs, can be set in the krb5.conf file with the tag names forward and forwardable respectively. Refer to the krb5.conf(4) manpage for more information on the appdefaults Section.

The fallback option can be set in the krb5.conf file within appdefaults Section. If fallback is set to true and the kerberos authentication fails, rlogin will use the non-secure mode of authentication.

Note: Command line options override the configuration file options.

-f: This option is only applicable in a secure environment based on Kerberos V5. It can be used to forward the ticket granting ticket (TGT) to the remote system. The TGT is not forwardable from there.
-F: This option is only applicable in a secure environment based on Kerberos V5. It can be used to forward the TGT to the remote system and have it forwardable from there to another remote system. The -f option and -F option are mutually exclusive.
-k realm: This option is only applicable in a secure environment based on Kerberos V5. It can be used to obtain tickets from the remote host in the specified realm instead of the remote host's default realm as specified in the configuration file krb.realms.

Escape Sequences

rlogin can be controlled with two-character escape sequences, in the form ex, where e is the escape character and x is a code character described below. Escape sequences are recognized only at the beginning of a line of input. The default escape character is tilde (~). It can be changed with the -e option.

The following escape sequences are recognized:

ey

If y is NOT a code character described below, pass the escape character and y as characters to the remote host.

ee

Pass the escape character as a character to the remote host.

e.

Disconnect from the remote host.

e!

Escape to a subshell on the local host. Use exit to return to the remote host.

If rlogin is run from a shell that supports job control (see csh(1), ksh(1), and sh-posix(1)), escape sequences can be used to suspend rlogin. The following escape sequences assume that ^Z and ^Y are set as the user's susp and dsusp characters, respectively (see stty(1) and termio(7)).

e^Z

Suspend the rlogin session and return the user to the shell that invoked rlogin. The rlogin job can be resumed with the fg command (see csh(1), ksh(1), and sh-posix(1)). e^Z suspends both rlogin processes: the one transmitting user input to the remote login, and the one displaying output from the remote login.

e^Y

Suspend the rlogin session and return the user to the shell that invoked rlogin. The rlogin job can be resumed with the fg command (see csh(1), ksh(1), and sh-posix(1)). e^Y suspends only the input process; output from the remote login continues to be displayed.

If you "daisy-chain" remote logins (for example, you rlogin from host A to host B and then rlogin from host B to host C) without setting unique escape characters, you can repeat the escape character until it reaches your chosen destination. For example, the first escape character, e, is seen as an escape character on host A; the second e is passed as a normal character by host A and seen as an escape character on host B; a third e is passed as a normal character by hosts A and B and accepted as a normal character by host C.

Remote Host Name As Command

The system administrator can arrange for more convenient access to a remote host (rhost) by linking remsh to /usr/hosts/rhost, allowing use of the remote host name (rhost) as a command (see remsh(1)). For example, if remotehost is the name of a remote host and /usr/hosts/remotehost is linked to remsh, and if /usr/hosts is in your search path, the command:

remotehost 

is equivalent to:

rlogin remotehost 

RETURN VALUE

rlogin sends an error message to standard error and returns a nonzero value if an error occurs before the connection to the remote host is completed. Otherwise, it returns a zero.

DIAGNOSTICS

Diagnostics can occur from both the local and remote hosts. Those diagnostics that occur on the local host before the connection is completely established are written to standard error. Once the connection is established, any error messages from the remote host are written to standard output, like any other data.

Error! could not retrieve authentication type.

Please notify sys admin.

There are two authentication mechanisms used by rlogin. One authentication mechanism is based on Kerberos and the other is not. The type of authentication mechanism is obtained from a system file which is updated by inetsvcs_sec (see inetsvcs_sec(1M)). If the system file does not contain known authentication types, the above error is displayed.

login/tcp: Unknown service

rlogin was unable to find the login service listed in the /etc/services database file.

There is no entry for you (user ID username) in /etc/passwd

rlogin was unable to find your user ID in the password file.

Next Step: Contact your system administrator.

system call:...

An error occurred when rlogin attempted the indicated system call. See the appropriate manual entry for information about the error.

EXAMPLES

rlogin remote 

Set the escape character to a !, use a seven-bit data connection, and attempt a login as user guest on host remhost:

rlogin remhost -e! -7 -l guest 

Assuming that your system administrator has set up the links in /usr/hosts, the following is equivalent to the previous command:

remhost -e! -7 -l guest 

WARNINGS

For security purposes, the /etc/hosts.equiv and .rhosts files should exist, even if they are empty. These files should be readable and writable only by the owner. See hosts.equiv(4) for more information.

Note that all the information, including any passwords asked for, is passed unencrypted between the two hosts. In a Kerberos V5 Network Authentication environment, a password is not transmitted across the network, so it will be protected.

rlogin is unable to transmit the Break key as an interrupt signal to the remote system, regardless of whether the user has set stty brkint on the local system. The key assigned to SIGINT with the command stty intr c should be used instead (see stty(1)).

AUTHOR

rlogin was developed by the University of California, Berkeley.

FILES

$HOME/.rhosts: User's private equivalence list.
/etc/hosts.equiv: List of equivalent hosts.
/usr/hosts/*: For rhost version of the command.